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2007, 26 (9): 0-0 doi:

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2007-09期中文目录

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STUDY ON PREDICTION OF HIGH WALL DISPLACEMENT AND STABILITY JUDGING METHOD OF SURROUNDING ROCK FOR LARGE CAVERN GROUPS

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2007, 26 (9): 1729-1729 doi:

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Taking the structural form of underground opening group of Ertan Project as the major background，and considering four basic factors，an expression that can predict the displacements of the key points on the high side walls of the underground houses is proposed through a great number of numerical analysis. Those basic factors include the deformation moduli of rocks，buried depths of openings，heights of major houses and lateral pressure coefficient of initial horizontal geostress component. The rock mass parameters have the implication of the matched strength indices of rock mass. The commonly used FLAC3D software is employed to conduct a great number of quasi 3D calculations about rocks stability. Using the second-order algebraic equations obtained through fitting that can predict displacements of high wall，both elastoplastic and elastic displacements of the key points on the side walls can be obtained rapidly. Then，the paper uses the above-mentioned equations to calculate the displacements of the key points of eight underground projects that have been completed or are being under construction or designing. Meanwhile，the calculation results are compared with the values from numerical analysis performed by former authors. The results show a good accordance between them，which indicates the effective nature of the above equations. Afterwards，three methods to judge whether surrounding rocks are stable，are put forward. The paper suggests that more commonly applicable method in-between them—the ratio of elastoplatic and elastic displacements is introduced as the main judging criterion. By using this criterion，the judgment on above-mentioned eight projects¢ surrounding rocks stability is carried out. On the basis of numbers of calculation results，the critical early warning value of the specific value of the above displacement ratio at different depths is given；and the linear equation to describe the relation between critical value and depth is also fitted. Considering a certain safety factor，the comparisons between the displacement ratio of side walls of the eight projects and corresponding critical value are made. Finally，the paper points out that the four projects among those eight are somewhat instable. So it is suggested that long cables should be used to reinforce the surrounding rocks to ensure the stability of these four projects. As a matter of fact，those four projects have introduced the reinforcing scheme by prestressed cables to support their high side walls already，showing that the proposed judging criterion is effective.

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INTEGRATED INTELLIGENT FEEDBACK ANALYSIS OF ROCK MECHANICS AND ENGINEERING PROBLEMS AND ITS APPLICATIONS

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2007, 26 (9): 1737-1737 doi:

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Several new methods for intelligent feedback analysis of rockmass models and their parameters are summarized. There include intelligent back analysis methods of mechanical parameters of rockmass，coupling recognition of the structure of the model and parameters，intelligent back analysis of variability of rock mass parameters in time and space，intelligent parallel finite element method with dynamical renew of the model and its parameters and integrated intelligent analysis of rock engineering safety with dynamical recognition of rock model and parameters. Among them，intelligent back analysis methods of mechanical parameters of rockmass include four kinds of methods such as uniform design(or ortho-design)-numerical method，practice swarm(or genetic algorithm) numerical method，uniform design(or ortho-design)-evolutionary neural network-numerical method- practice swarm(or genetic algorithm) and uniform design(or ortho-design)-evolutionary support machine- parallel numerical method-practice swarm(or genetic algorithm) method. Several key problems to obtain global optimum solutions for the back analysis of rock model and parameters are also discussed. Finally case studies have been given to show applicability of the new methods.

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ON BASIC CHARACTERISTICS AND INNOVATION OF YIELD CRITERIA FOR GEOMATERIALS

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2007, 26 (9): 1745-1745 doi:

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A number of yield criteria have been proposed. Most yield criteria satisfy one or some basic characteristics of yield criterion. For examples，the Tresca yield criterion is a single-shear criterion；the strength difference(SD) effect，effect of normal stress，effect of intermediate principal stress，effect of intermediate principal shear stress，effect of hydrostatic stress，and the effect of twin-shear stresses are ignored. The Mohr-Coulomb yield criterion satisfies the SD effect，effect of normal stress，effect of single-shear stress and effect of hydrostatic stress. However，the effect of intermediate principal stress，effect of intermediate principal shear stress，and the effect of twin-shear stresses are not taken into account. The Drucker-Prager yield criterion can not satisfies the effect of stress angle. The basic characteristics of yield criteria are available for the research and innovation of yield criterion. The innovation of yield criterion for geomaterials has to satisfy three elements of scientific innovation as follows：(1) new(not existing before，introduced for the first time)；(2) better than existing criteria；and (3) availability for application. The development of mechanical models for various yield criteria is summarized. According to a new pentahedron mechanical model，a tension-cut condition is added to the unified strength theory. The unified strength theory is extended to the tension region for geomaterials.

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STUDY ON LOW STRAIN DYNAMIC RESPONSE THEORY FOR ANCHOR BARS-SURROUNDING ROCK SYSTEM AND ITS APPLICATION

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2007, 26 (9): 1758-1758 doi:

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The low strain longitudinal dynamic model of anchor bars-surrounding rock system under impulse force is established. The model is essential to nondestructive detection of anchorage system quality. Through theoretical study，model experiment and numerical simulation，the characteristics of dynamic response with different defects in the anchor bars are studied. In dynamic analysis，the variations of dynamic parameters reflect the damaged degree of anchorage system and dynamic parameters are the vital reference of the anchorage quality. The simplified models of anchorage system with different damage conditions are constructed in laboratory；and a new approach which uses genetic algorithm is employed to solve the problem of multi-parameter inversion for anchorage system in dynamic testing. By modern signal processing and artificial intelligent methods，the method of fixing defect position and structure identification of anchorage system are researched. Meanwhile，a quantitative assessment method of anchoring quality is put forward；and an intelligent diagnosis system for nondestructive evaluation of anchorage system is established and applied to field engineering.

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DIRECT SHEAR TESTS FOR LAYERED SALT ROCKS OF YUNYING SALT MINE IN HUBEI PROVINCE

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2007, 26 (9): 1767-1767 doi:

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For investigation on the characteristics of shear deformation and strength of layered salt rocks in Yunying Salt Mine，Hubei Province，direct shear tests on three types of rocks are carried out. It is shown that the curves of shear stress vs. displacement of salt rock，anhydrite and layered salt rock are similar：during the beginning stage of shear loading，the slope coefficients are small，the shear displacement increasing fast while the shear stress increasing slowly；when the shear stresses reach a certain value，the increase of shear displacement slows down，and the slope coefficients get larger；the increase of shear displacement becomes fast again prior to shear stress reaching peak value；after peak point，strain softening appears，the shear stresses decreasing slowly and reaching residual strength finally. The test results also show that the shear strength of layered salt rocks is close to or even slightly higher than that of salt rock and anhydrite：cohesive strength MPa，and frictional angle 45.9°. This indicates that the interfaces between salt rock and anhydrite are not weak as expected. The strong interface property of layered salt rocks will guarantee the sealability and stability of salt caverns，and benefit the energy(oil and gas) storage in layered salt rocks formation in depth.

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SIMULATION OF TOPPLING FAILURE OF ROCK SLOPE BY NUMERICAL MANIFOLD METHOD CONSIDERING FRACTURE OF ROCK BRIDGES

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2007, 26 (9): 1773-1773 doi:

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By adding the function of tracing the propagation of cracks，the numerical manifold method proposed by Dr. Shi Genhua is developed which can simulate both the discontinuity of block system and the tensile or shear failure of intact rock. Based on the examination of convergence and accuracy through several typical and simple cases，the centrifuge test that is employed to model the toppling failure of high rock slope on the left bank of Longtan Hydropower Station is simulated，which considers one set of connected opposite-slope joints with steep-dips and one set of along-slope cracks which are not disconnected with low-dips. In this numerical simulation，the propagation of disconnected cracks and the fracture of rock block under external loads are simulated；both the bearing capacity and failure mode simulated numerically are in well coincidence with results of the test，which presents the mechanism of toppling failure of slopes of this kind again. Also，it shows that the proposed method and the program developed can effectively simulate the toppling failure of rock slope while considering the effects of rock bridges.

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ANALYSIS OF VISCOELASTIC DEFORMATION BEHAVIOR OF SHALLOW-BURIED DECOMPOSED-ROCK TUNNEL AFTER PRELIMINARY SUPPORT

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2007, 26 (9): 1781-1781 doi:

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In order to analyze the viscoelastic effect of shallow-buried decomposed-rock tunnel surrounding rock deformation with time after preliminary support，the analytic solutions of equivalent elastic modulus and equivalent coefficient of confining pressure were derived adopting inverse back analysis methods firstly. Secondly，taking the concrete engineering practice of shallow-buried and blind excavated decomposed-rock tunnel for example，which belongs to the shore segment of Xiang¢an subsea tunnel engineering in Xiamen，Fujian Province，and the representative sections and collecting their surrounding rock measured displacement data after preliminary support are selected，the regularity of the ratio of equivalent coefficient of confining pressure to equivalent elastic modulus varying with time after surrounding rock preliminary support of this type tunnel was derived by the analytic means of mathematic statistics；and the representative sections and collecting their surrounding rock measured displacement data after preliminary support are selected. Finally，the viscoelastic model of surrounding rock deformation after preliminary support is established；and its viscoelastic effect of deformation with time was researched. The research results show that in the first place，the ratio of equivalent coefficient of confining pressure to equivalent elastic modulus increases in monomolecular growth model without external action such as rainfall after shallow-buried decomposed-rock tunnel surrounding rock preliminary support；and it will finally be stabilized. Namely，the viscoelastic effect of surrounding rock deformation varying with time agrees with this regularity also；and the surrounding rock deformation varies in the inverse ratio of equivalent coefficient of confining pressure. In addition，in the tunnel segment of surrounding rock with higher stiffness and weak groundwater moving，the deformation of surrounding rock may converge more rapidly after its preliminary support.

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AN IMPROVED NEWMARK SLIDING BLOCK METHOD BASED ON STICK-SLIP COUPLED DYNAMIC RESPONSE

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2007, 26 (9): 1787-1787 doi:

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Earthquake-induced sliding displacements of earth structures are generally evaluated using sliding block analyses that do not accurately model the seismic response of the sliding body or the exciting loads along the sliding plane. The traditional decoupled approximation introduced to capture each of these effects separately is generally unreasonable. A simple coupled analytical model based on the rules of resistant earthquake of sliding-isolated structures，which captures simultaneously the response of the sliding mass and the nonlinear stick-slip sliding response along the sliding plane，is presented. In this method，as the sliding is initiated，the sliding acceleration is substituted directly in motion equation as one loading item to get the increment of sliding displacement. The modified motion equation shows that high inertial forces can nevertheless develop in a sliding mass at the beginning of each sliding process because of the additional inertial forces resulted from the transient sliding acceleration，while the sliding surfaces might limit energy transmission. Moreover，the fundamental period of sliding acceleration is about half of the mean period of the input motion in the processes of sliding. The proposed Newmark sliding model is validated with Wartman¢s shaking table experiments of deformable soil columns sliding down an inclined plane. The correlation between plastic sliding displacement and the dynamic response of earth structures is evaluated，and comparisons are made between proposed and decoupled analytical methods with linear material properties based on results of sliding displacements and amplitudes of dynamic response in sliding direction through a deformable soil column and a practical retaining wall. It is shown that the differences between the two approaches are remarkable；the plastic sliding deformation can limit effectively the amplitude of dynamic response in sliding direction and the decoupled will lead to conservative results.

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EXPERIMENTAL STUDY ON PROPAGATION AND COALESCENCE MECHANISMS OF 3D SURFACE CRACKS

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2007, 26 (9): 1794-1794 doi:

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A series of uniaxial compressive tests on the frozen PMMA with pre-existing 3D cracks were performed in laboratory to investigate the mechanisms of crack propagation and coalescence in brittle materials. It is found that for 3D surface cracks，the interactions of cracks affect crack growth and extension in two aspects，i.e. the interaction either prompting crack extension or restraining it. The mechanism of crack interaction depends mainly on the location of cracks in spatial domain. The propagation and coalescence of 3D surface cracks are dependent on the crack depth and the crack configuration. The test results are helpful to more understanding of the failure mechanism of brittle materials including PMMA and also to the study of the failure mechanism of rock under loading.

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DAMPING COEFFICIENTS OF PILE-SOIL INTERACTION WITH LOW STRAIN

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2007, 26 (9): 1800-1800 doi:

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The pile-soil interaction-damping coefficient with low strain is a key parameter to quantitatively analyze defects of piles. The pile-soil interaction equation was established to determine the damping coefficient using experiments. The time-history velocity at pile top was analyzed corresponding to different damping coefficients and free-end boundary condition. The relationship between the incident and reflected velocity amplitudes ratio at the pile top and the coefficient was developed. Six types of soils were selected to conduct pile-soil interaction model tests and determine the coefficient for different effective overburden pressures，unsaturated and saturated states. Effects of soils and the effective overburden pressure on the coefficient were researched. The experimental results show：(1) the exponential relationship can be used to describe the increment of coefficients with the effective overburden pressure for six soils，but determining coefficients in the relationship are different for different soils；(2) damping coefficients of saturated sands and silts decrease 25% to 60% compared with the coefficients of unsaturated sands and silts. If the effective overburden pressure varied from 85 kPa to 850 kPa，the damping coefficient of the saturated silty clay increased from 250 s－1 to 890 s－1. However，if the effective overburden pressure varied from 20 kPa to 150 kPa，the damping coefficient of the saturated soft clay will increase from 330 s－1 to 420 s－1. The test results were also compared with damping coefficients determined using other methods to show the necessity of determining damping coefficients using the model test method.

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STUDY ON METHOD OF ORIENTATION DATA PARTITIONING OF RANDOMLY DISTRIBUTED DISCONTINUITIES OF ROCKS

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2007, 26 (9): 1809-1809 doi:

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Clustering method is a single-objective optimal method in nature，a prior specified number of clusters and the initial cluster centroids must be given in advance，and different choices of initial guesses of cluster centroids can lead to different partitions of the same data. The new representation proposed in this paper deals with the partitional clustering problem by regarding it as a multi-objective optimal problem；in this approach the niche Pareto genetic algorithm is used to solve the problem. Aiming at clustering problem，a linked-list based encoding scheme and accordingly genetic operators are presented. With the introduction of niche technique and Pareto dominant set theory，the optimal partitions for all possible numbers of clusters in the Pareto optimal set returned by a single GA run are obtained. The performance of the proposed approach has been tested using artificial data and the data form real rock mass of the shiplock high slope of the Three Gorges Project. The obtained results are promising and demonstrate the applicability and effectiveness of the proposed approach.

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EXPERIMENTAL STUDY ON EFFECT OF TOPOGRAPHY ON PROPAGATION OF BLASTING WAVES

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2007, 26 (9): 1817-1817 doi:

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The law of propagation of vibration wave of blasting is mostly affected by property of rock material and parameters of explosive loadings，whereas the topography affects greatly propagation of vibration wave under condition of a variety of terrains. Many explosion tests are carried out in the second period engineering project in Ling¢ao Nuclear Power Station，Guangdong Province. The dissemination of vibration wave of blasting is analyzed in concave or protruding topography. The results show that the concave landforms have great effects on decreasing scale of vibration wave of blasting. It is found that the attenuation coefficient of vibration wave in concave landform is relative to its width and depth and to charge weight per delay interval and explosive distance. The protruding topography can enhance scale of vibration wave of blasting The amplification effect is related to orientation in protruding topography，and that the vertical vibration velocity is amplified more than that of the horizontal vibration. The amplified coefficient of vibration wave blasting is augmented with relative altitude，but decreases with the scale distance of explosive in protruding topography. In addition，the scale effect of protruding landform is also related to property of rock mass，and the structure of rock and the growth of cranny.

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THREE-DIMENSIONAL RANDOM SEEPAGE FIELD ANALYSIS FOR MAIN EMBANKMENT OF YANGTZE RIVER

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2007, 26 (9): 1824-1824 doi:

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Since the complicacy of practical seepage problem effected by various random factors，the three- dimensional simulation and analysis for stochastic seepage field has an important meaning in engineering applications. The three-dimensional anisotropic heterogeneous steady random seepage model and designed program are developed on the basis of finite element method. A statistical analysis of stratum soil characteristics and geological columns sampled from the main embankment of Yangtze River in southern Jingzhou zone of China is carried based on practical engineering projects. The statistical hypothesis of Gaussian probability distribution for random permeability tensors of soils to be submitted into the stochastic seepage field simulation was verified that this assumption would be accepted by the statistical testing based on Kolomogorov-Smirnov theory. Various statistical characteristics and random natures in random seepage fields of the main embankment of Yangtze River in southern Jingzhou zone of China were investigated by numerical analysis for stochastic seepage fields simulations using three-dimensional finite element method as well as the rationality of simulated stochastic results；and the developed model was also examined through statistical testing. Especially，the random variation of upstream and downstream water levels as a stochastic boundary condition was considered for the three- dimensional finite element model of practical analysis of the random seepage field simulations in order to describe disturbed effects of the boundary randomness due to variability of downstream and upstream water levels over variability of simulated results presented by vector series of the random seepage field. Furthermore，the functions of some safeguards to set up against the seepage problem，such as sheet-pile breakwater and catch-water，as the turbulence of complex boundary condition together with the effects of variability of soil permeability have been analyzed for description of influences on the hydraulic potential distributed in the random seepage field and compared with the result obtained by analyzing the corresponding steady seepage field problem. That presents the necessity，feasibility and practicability of employing stochastic studies in seepage field problems. The developed method provides a more detail and full stochastic algorithm to characterize and analyze three-dimensional random seepage field problems. The conclusion of simulated analysis is reliable in comparison with pertained stochastic checking and measured data from practical engineering.

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FRACTURE MORPHOLOGY ANALYSIS OF BRITTLE ROCK UNDER ANTI-PLANE SHEAR(MODE III) LOADING

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2007, 26 (9): 1832-1832 doi:

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An anti-plane punch-through shear test and an anti-plane compression-shear box test are applied to the study of fracture mechanism of brittle rock under the anti-plane shear(mode III)loading. For the anti-plane punch-through shear specimen，the fracture trajectories is a helicoid and the microscopic surface is formed by intergranular fracture. The most crystals have three steep step surfaces with many river-typed patterns and fish- born patterns，which represent the tensile fracture(mode I). For the anti-plane compression-shear specimen，the crack appears and propagates almost along its original plane. The microscopic characteristic is of transgranular fracture. The crystal surface displays many dense parallel patterns；and rock fragments indicate the shear fracture(mode III). Finite element method is used to investigate the fracture mechanism under anti-plane shear loading. Numerical results show that both tensile and shear stresses exist at the crack tip. The addition of compressive stress on the original crack plane can depress the tensile stress at the crack tip and facilitate the crack to initiate and propagate along its original plane；i.e. anti-plane shear mode III fracture. The ratio of maximum shear stress to maximum tensile stress tmax/s1 is 5–10. Since too large or too low inclination angle a can result in small compressive stresses or local crush；the suggested inclination angle a is 55°–70°. The anti-plane compression-shear box test is a potential method for realizing fracture mode III and determining its toughness KIIIC of brittle rock.

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EVALUATION OF EFFECTS OF SEEPAGE ON LANDSLIDE REINFORCED BY ANTI-SLIDING PILES

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2007, 26 (9): 1840-1840 doi:

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The anti-sliding piles have been used in the treatment of geological hazards；the construction technology and theories of anti-sliding piles have been researched and developed. After the construction of the anti-sliding piles is completed，the effective seepage section of landslide will diminish，the underground water level of landslide will increase，the unit weight of landslide will increase but the effective cohesion and friction angle of sliding zone of landslide will decrease. The designed anti-sliding stability of landslides after pile construction is studied. The effects of landslide treatment by anti-sliding piles are also investigated by using volume average method，self-consistent method and Hashin-Strikman method；an available method is proposed to evaluate the effectiveness of anti-sliding pile reinforcement. Finally，the stability of landslide reinforcement by anti-sliding pile is performed. The effect of anti-sliding pile treatment is evaluated.

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DESCRIPTION METHOD OF DARCY¢S LAW IN LARGE-STRAIN OF FLUID-SOLID COUPLING

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2007, 26 (9): 1847-1847 doi:

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The large-strain description method for the constitutive equation of fluid flow in fluid-solid coupling theory is studied for different reference configurations. Using the coordinate transform method，the strain tensor transformation relation and the objectivity hypothesis，the rational forms of Darcy¢ law in both spatial description method and material description method are derived respectively，as well as the seepage coefficient expression for large-strain deformation coupling. The results of both experimental and case analysis show that the differences of seepage coefficients between different description methods increase with the development of material deformation；and the ignorance of the effect of reference configuration for large-strain problems will lead to a considerable big error. The large-strain seepage coefficient(FSSC) considering deformation coupling is greatly influenced by both material and geometrical nonlinearities. The behavior of mathematical monotonicity for FSSC is more complex than that for the large-strain seepage coefficient.

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STUDY ON GROUND SETTLEMENT INDUCED BY SHALLOW METRO STATION CONSTRUCTIONS

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2007, 26 (9): 1855-1855 doi:

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For studying the effects of ground movements on pipelines and structures，prediction of ground settlement induced by tunneling is always a hot issue. A regression analysis of the field measurements of ground settlements induced by shallow metro station constructions in Beijing is conducted to acquire empirical estimations of the relevant characteristic parameters. The ground conditions include silty sand，silty clay，clayey silt，silty fine sand，medium and coarse sands，cobble and gravel，which are typical of soil compositions in Beijing area. About 69.8% of the maximum ground settlements induced by the station constructions are less than 60 mm. The accumulative frequency curve of maximum surface settlement fits well with the accumulative normal distribution curve. The parameter of settlement trough is dependent on the construction method：0.61–0.82 for drift-PBA method，and 0.40–0.65 for central drift method. The ground loss ratio is 0.39%–1.41% for drift-PBA method；and the average loss ratio is 0.93%. For central drift method，the ground loss ratio is 0.49%–1.03%，and the average is 0.69%. These results are useful for predicting the magnitude and influential range of ground settlement.

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EXPERIMENTAL STUDY ON BEHAVIOUR OF UNSATURATED REMOULDED CLAY SUBJECTED TO DRYING AND
WETTING CYCLIC PATHS

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2007, 26 (9): 1862-1862 doi:

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The empirical relationship between matric suction and void ratio on drying path for remoulded clay is established by utilizing the shrinkage curves and the soil-water characteristic curves which are determined through experimental tests. The result shows that increase of suction can¢t cause shrinkage of soil sample when matric suction reached a specific value which is defined as the shrinkage limit suction ss. The process of shrinkage of soil is divided by yielding suction s0 and shrinkage limit suction ss into three stages，i.e. elastic stage，elastoplastic stage and stage of shrinkage limit. In order to study the soil water characteristic curve and shrinkage coefficient under different net mean stresses，using GDS unsaturated triaxial apparatus，the total volume change and water content change are examined under controlled net mean stress in a predetermined stress path. The results show that shrinkage index and the soil-water characteristic curve are dependent on net mean stress. In addition，in wetting stage，i.e. zero suction is applied to soil samples in saturated state，the swelling takes place under lower net mean stress. Under higher net mean stress，however，swelling in the beginning is followed by a certain volumetric contraction.

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A HYBRID MESHLESS FINITE VOLUME METHOD AND ITS APPLICATION

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2007, 26 (9): 1868-1868 doi:

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To avoid mesh restriction，the finite volume method(FVM) is combined with the meshless method based on the moving least squares(MLS) approximation. A hybrid meshless finite volume method(MFVM) is presented. Here，“hybrid” has the same meaning as the hybrid finite element. By the hybrid technique，both the displacement and the stress are independently interpolated. In this way，the derivatives of shape functions in integrand on the process of sub-domain integration will disappear. Then，the stress-displacement compatibility is implemented by the collocation method. Essential boundary conditions are imposed using a modified collocation technique. Numerical results in the case studies show that the presented method has higher accuracies and computational efficiencies.

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EXPERIMENTAL STUDY ON RHEOLOGICAL REGULARITY AND CONSTITUTIVE RELATIONSHIP OF ROCK UNDER DISTURBING LOADS

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2007, 26 (9): 1875-1875 doi:

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The concepts of disturbing load and disturbing rheology of rocks are put forward on the basis of real production processes and self-developed disturbing rheological instruments with ordinary triaxial box and disturbing load device are simply introduced. Using MTS and the self-developed disturbing rheological instrument with ordinary triaxial box and disturbing load devices，tests of rock rheology under compression and compression rheology under disturbing loads as well as tensile rheolegy under tensile stresses of two typical rocks(red sandstone and soft mudstone) are carried out. Through analyzing the data of rheological tests，some important conclusions are drawn as follows：(1) disturbing rheological strain of rock is much greater than the instantaneous strain and rheological strain of rock under the same stress；(2) each disturbing load can always cause a mutation of strain and the mutation of strain is in direct ratio to static stress s as well as disturbing stress Δs；and (3) for each rock，there is a sensitive range of the static stress s and disturbing stress Δs，etc.. Through analyzing the data of tests，a rheological constitutive equation as a function of disturbing load and stress as well as time is established；and the constitutive equations are proven with test data. Moreover，the sensitive range of static stress and disturbing stress to produce disturbing rheology is also studied. The studies of rock disturbing rheological test and disturbing rheological theory may extend the content of the theory for rock rheology and support design of soft rocks.

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MEASUREMENT AND ANALYSIS OF BLASTING VIBRATION IN HESHANG THREE-LANE TUNNELS WITH SMALL CLEAR SPACE

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2007, 26 (9): 1882-1882 doi:

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According to the construction of Heshang three-lane tunnels with small clear space in Fuzhou international airport highway，the monitoring of blasting vibration was carried out. Based on measured data，the propagation and distribution characteristics of vibration waves in the rock mass were analyzed. Some conclusions have been drawn. Vibration speed at tunnel wall is greater than that at the foot of the wall；and the better the rock mass quality is，the less differences the vibration speeds at the two places are. The maximum vibration speed occurs at the radial direction of tunnel wall facing the blasting side，which can be regarded as the controlling vibration speed. When the clear distance of two tunnels is 6 m(about 0.35B)，the disturbance range of blasting vibration to inter-space rock is 10–20 m apart from the blasting working face. The better the quality of rock mass is，the less the disturbance range is. And the blasting has more influences on the rock in front of the blasting face than that behind of the blasting face. In addition，the total explosive volume should be strictly controlled and decreased，as well as the single segment，and the blasting segments interval time should be greater than 100 ms. The experience and conclusions presented can be referred in the blasting controlling and site monitoring of similar tunnels.

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ANALYSIS OF PRESTRESS VARIATION OF CABLE IN MUDSTONE HIGH SLOPE REINFORCEMENT

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2007, 26 (9): 1888-1888 doi:

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Cable is widely used in slope reinforcement engineering；the rules of prestress change in cable are not studied thoroughly and systematically yet，especial the prestress loss after lock and the lasting prestress of cable in mudstone slopes. Based on the systematical monitoring and analysis in the slopes reinforcement project，the prestress loss after lock with short-term and long-term prestress change rules are studied；and also the influence of rainfall on the cable prestress state and the compensation method are monitored and discussed. It is found that the prestress loss after lock is about 12.8%；and the reason is anchorage circle caused by the retraction. After being locked，the prestress loss can be divided into three stages. The first stage lasts about a half month after being locked；but the prestress loss velocity is quickly，about 6.2% in 15 days. It is mainly caused by the creep of mudstone after the cable is locked. Then it becomes into a relatively slow stage：the prestress loss is about 8.1% and the time lasts for about 6 months. Finally，the pretress comes to a steady stage，in this stage the prestress loss is seldom seen but also can be influenced by rainfall etc.. The compensation method can raise the prestress for about 15.4% and also can reduce the lost ratio. By studying the rules of prestress changes in the mudstone slopes，the influencing factors and the compensation method are analyzed.

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REFINED MODELING FOR NUMERICAL SIMULATION OF ENGINEERING ROCK MASS STRUCTURES BASED ON 3D
GEOLOGICAL MODEL

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2007, 26 (9): 1893-1893 doi:

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Aiming at the difficulties of geological modelling and space unit division in pre-processing of numerical simulation analysis for engineering rock-mass structures，the coupling pattern and method of 3D geological model with numerical simulation are put forward to simplify the pre-processing. The refined 3D engineering geological integrated model was built by the 3D geological modelling system in the research area. Then，the element mesh model could be generated automatically. Subsequently，the model data were converted and imported to numerical simulation programs；and it offered different kinds of 3D mesh division models with abundant information. It can not only simplify the pre-processing of numerical computation and analysis，but also is abounding with the attributive information of 3D geological models. And it will offer a visual and convenient information platform for engineering design and optimization.

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A NEW RHEOLOGICAL MODEL ELEMENT FOR GEOMATERIALS

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2007, 26 (9): 1899-1899 doi:

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A soft-matter element and its constitutive equations were presented by employing the Riemann- Liouville fractional calculus operator theory. The element could be used to simulate the soil of which behaviors were deemed as the materials between perfect solid and fluid；it also could be used to describe the nonlinear slow-variable process of stress-strain in stress relaxation or creep. Two new models were determined when a soft-matter element was parallel to or series connected with an elastic element. The constitutive equations，relaxation modulus and creep modulus could also be obtained. A rheological trial fitting curve of soil was provided. The achieved results show that the proposed model with soft-matter element was more efficient in describing the rheological characteristics of soil and could reduce the number of parameters.

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BOOTSTRAP FUSION AND ITS GREY HYPOTHESIS TESTING FOR LANDSLIDE TIME SERIES OF MULTI-SENSOR

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2007, 26 (9): 1904-1904 doi:

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Time series of multi-sensor belong to non-stationary random process. Based on bootstrap of statistics and grey relational analysis of grey system theory，a method called BFGT(bootstrap fusion and grey testing) is proposed to resolve the problem about optimum fusion and its hypothesis testing for landslide time series of multi-sensor. By means of bootstrap resampling method and maximum entropy theory to imitate bootstrap distribution of time series of multi-sensor at different hours and in different positions，some of instantaneous features of the landslide process are depicted. Extracting these instantaneous features via calculation of the weighting mean using bootstrap distribution，bootstrap fusion series are formed. And grey rejection region of hypothesis testing for compatibility of time series of multi-sensor through definition of concepts，grey difference，attribute weight mapping and grey confidence level. By using time series information from distributed system of multi-sensor placed in different positions，the BFGT can simulate both transient state and evolvement process of overall landslide，which are described with maximum entropy probability distribution. In addition，by the aid of weighting mean value estimating technique of maximum entropy probability，the BFGT can identify probability distribution of the noise from information sources of multi-sensor at the same hour，reducing the noise，and then weakening influence of the noise on estimated results. Engineering application in landslide shows that the BFGT permits trend of non-stationary random process unknown and the number of data small without any requirements for probability distribution，having the lowest grey confidence level of 90% and the mean grey confidence level of 95%.

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NUMERICAL ANALYSIS OF SHORT FIBER REINFORCED CEMENT-BASED COMPOSITES IN DIRECT TENSION

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2007, 26 (9): 1913-1913 doi:

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soft region was defined as a local region including microcrack，microdefect，etc. based on mesoscopic mechanics method；and it was assumed that mortar specimen was composed of mortar matrix and many soft regions are distributed in the matrix. In terms of Monte Carlo random sampling principle，it could be acquired that soft region elements are randomly distributed in the matrix. Material heterogeneity of matrix elements and soft region elements were depicted with Weibull parameters，and matrix elements and soft region elements were in accordance with low tension crack law，thus mortar tension numerical model can be built. Considering effects of distribution of soft regions，Weibull distribution parameters，mesoscopic element mechanical parameters on numerical experiments，the mechanical behaviors of mortar tension crack are analyzed. Based on mortar tension numerical model，short fiber reinforced mortar numerical model that was treated as three-phase composites including matrix，soft region and short fiber，was also built. With the numerical model，tension crack behavior of short fiber reinforced mortar was researched；the effects of fiber mesoscopic mechanical parameters such as fiber length，fiber diameter，fiber distribution characters on numerical tension results were also analyzed. Finally，numerical results were compared with experimental data，and the results display that numerical model can successfully simulate mortar tension crack and strengthening character of short fibers with mortar. The complete curve of mortar tension stress-strain agrees well with experimental results.

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ANALYTICAL ANALYSIS OF INTERACTION OF SUPERSTRUCTURE-STIFFENED AND RECTANGULAR RAFT -SOIL

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2007, 26 (9): 1923-1923 doi:

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Considering the stiffened plate as a composite system of grillage beams and slab，the superstructure as an equivalent rigidity plate，a semi-analytical and semi-numerical method，which makes use of compatible analysis of force and displacement among beams and slabs and columns and ground，is developed to analyze interaction between stiffened raft foundation and subsoil considering the rigidity of superstructure. The method has good preciseness and less unknown variables and it is convenient to be used in practice. Numerical examples and practical engineering case both show that superstructure rigidity has an important influence on deformation and interal force of stiffened raft foundation；and practical engineering proves that the presented method has good preciseness and practicality. Especially，it is convenient to calculate the coefficient of subsoil settlement with the data of geotechnical engineering investigation.

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LAGRANGE INTERPOLATION FOR MULTI-LAYER GROUND IN CONSOLIDATION OF PARTIALLY PENETRATED VERTICAL DRAINS

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2007, 26 (9): 1932-1932 doi:

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Considering the well resistance and the smear effects，the numerical modeling and the solution method for multi-layered clays consolidation by partially penetrated vertical drains under time-dependent loading are presented. Assuming a virtual drain penetrating the soft strata at the bottom of the actual drain，the partially penetrated vertical drain is transformed into a fully penetrated vertical drain，thus the boundary conditions for consolidation equations and the numerical process are simplified. The excess pore water pressure of each stratum is interpolated and approximated by Lagrange interpolation polynomials；and the algebraic equations of excess pore water pressure at boundary nodal points are obtained with inner nodal points. Thus the consolidation equations of the section with vertical drains are transformed into simple differential equations describing the values of excess pore water pressure in the nodes，and linear algebraic simultaneous equations of vertical drains consolidation in the nodes are obtained simultaneously. For the four-layer soils，the calculating formulas are presented in detail. If the number of soil layers is added，the boundary nodal coefficient formulas are changed only. The presented numerical results are compared with those using the relevant approximate methods；and an example of roadbed composed of four soft soil layers under preloading is analyzed. It is shown that there are no much differences between the one-dimensional model and the three-dimensional model adopted in the underlying undrained zone.

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EFFECT OF SAMPLE DISTURBANCE ON SOFT SOIL STRENGTH

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2007, 26 (9): 1940-1940 doi:

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Soil disturbance degree(SD) defined by Z. Hong and K. Onitsuka is used to analyze the relationship between SD and parameters of soil strength；and the function with the soil strength，disturbance degree and soil sensitivity are established. It is found that the soil yield stress of high sensitivity soil changes greatly when disturbance obeys to the function. Then，the relationships between the soil shear strength，tip resistance of CPT，confined modulus and soil disturbance are discussed. At last，the laboratory vibrating model tests are carried out to simulate soil disturbance；and samples with different vibrating times are performed with different disturbance degrees. After vibrating，odometer tests and unconfined compression tests are performed；and reliability and reasonability of the function and relationship are validated.