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null

2004, 23 (12): 0-0 doi:

[PDF] 138 KB (771)

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DAMAGE DETECTION USING WAVELET TRANSFORM OF SPATIALLY DISTRIBUTED SIGNAL FOR ROCK MATERIALS

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2004, 23 (12): 1961-1961 doi:

[PDF] 282 KB (962)

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Based on wavelet transform of spatially distributed signal，a new damage detection method is put forward. The rationale of this method is that damage of rock materials will cause perturbations of measured structural signal at damage sites. Although the exact location of damage can not be specified directly by the raw measured signals，it becomes discernible from component wavelets of the signals. The viability of this new technique is demonstrated with a test，in which the cylindrical samples made from cement and sand are examined by sound wave emission，and the amplitudes of head wave at different sites along the axis of cylindrical samples can be obtained. Then wavelet transforms are performed on the measured data. The sites of damage correspond to the sites at which great fluctuation occurs in the curve of wavelet coefficient. The results indicate that the presented method is feasible.

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STUDY ON BRITTLE ROCK FAILURE CRITERION BASED ON STRAINS

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2004, 23 (12): 1966-1966 doi:

[PDF] 245 KB (970)

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When rocklike materials are tested in triaxial compression，two kinds of failure，ductile failure and brittle failure，may happen. Rock failure essentially results from the relative displacement among mineral particles. Generally，rock failure can be either tensile or shear，depending on which mechanism is predominant during the failure process. The maximal tensile strain criterion can predict rock failure in tension，but cannot explain the crack angle. Rocks are generally anisotropic. The principal strain axes are usually different from the loading axes. Therefore，strains in the directions of the loading axes may not be suitable to describe rock strength. The strain-based strength criterion considering tensile strains in three axes can describe rock strength. And it can describe the crack angle and its transformation. Theoretical analyses and laboratory tests have validated this conclusion. With the increase of the intermediate principal stress，the transformation of the strain failure criterion is of the same pattern as the transformation of the compressive strength criterion and the maximum tensile strain criterion.

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STUDY ON ELASTOPLASTIC CONSTITUTIVE MODEL OF ROCK
WITH STATISTICAL DAMAGE

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2004, 23 (12): 1971-1971 doi:

[PDF] 179 KB (975)

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Using the Eshelby equivalent inclusion method，a statistical constitutive model for elastoplastic and damaged rock is set up，which can reflect the relation between stress and strain and the relation between axial strain and traverse strain before the rock fails. The hypothesis that the relation between the total strain and the strains in phases and the relation between the total stress and the stresses in phases are different is empoyed. An optimization method is developed to determine the parameters of the constitutive model. The presented model is verified by the experiments.

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DEFINING DAMAGE VARIABLE BASED ON ENERGY DISSIPATION

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2004, 23 (12): 1976-1976 doi:

[PDF] 271 KB (2177)

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Constitutive energy and dissipation energy in material deformation are analyzed. Dissipation energy is calculated according to cycling loading test. A formula of damage definition in theory is suggested，and the calculation method of damage variable is given as well. The rule of damage development is studied in tests.

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DETERMINATION OF REASONABLE POSITION AND STABILITY ANALYSIS OF FINISHING CUT IN FULLY-MECHANIZED
COAL FACE WITH TOPPED CAVING

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2004, 23 (12): 1981-1981 doi:

[PDF] 341 KB (1039)

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The removal speed of the fully-mechanized coal face with topped caving (FCFTC) can be increased by pre-excavating finishing cut on terminal mining line. Because the finishing cut is continuously affected by the abutment pressure in front of the face，its maintenance is much more difficult than that of the ordinary coal entry. Based on the law of the ground pressure and the the motion of overlying strata during the terminal mining in FCFTC，in order to avoid the influence of periodic roof pressure，the optimal position of finishing cut is determined by analogous simulation experiment. The stability of the surrounding rock masses of finishing cut is analyzed systemically and its support design is optimized by numerical simulation with RFPA2D. The application of the analysis results to 4303 FCFTC of Jisan Coal Mine shows that the finishing cut is safely jointed to coal face and the coal face finishes quickly. The effect of the finishing cut and its economic benefit are also evaluated.

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STABILITY ANALYSIS OF SURROUNDING ROCK MASSES OF ROADWAY
UNDER OVERHEAD MINING

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2004, 23 (12): 1986-1986 doi:

[PDF] 353 KB (1039)

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Considering the relative position of working face and the floor roadway，the stress evolution of surrounding rock masses，rock displacement around floor roadway induced by overhead mining，and the roadway stability at different position are analyzed in detail by numerical simulation. The results show that the abutment pressure distribution on coal pillar is the direct reflection of abutment stress induced by mining on the interfaces of coal seam and immediate roof. The rock displacement around roadway under nearby overhead mining is influenced by the whole displacement induced by mining as well as abutment pressure on the coal pillar. The floor roadway should be located out of the abutment stress zone when protection coal pillar is retained，or the working face should be pushed away for enough distance under overhead mining. The study result is proved by a case analyzed.

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ENTROPY CATASTROPHE CRITERION OF SURROUNDING
ROCK STABILITY

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2004, 23 (12): 1992-1992 doi:

[PDF] 180 KB (1174)

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Surrounding rock masses of underground engineering are of high nonlinear characteristics，so their mechanical behavior can be studied and predicted by nonlinear theories. Research is made on surrounding rock stability with dissipative structure theory and catastrophe theory to unveil procedures and causes of rock failure. A method is developed to analyze the stability of surrounding rock masses.

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CUSP CATASTROPHIC MODEL OF INSTABILITY OF STRIP COAL PILLAR ALONG STRIKE

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2004, 23 (12): 1996-1996 doi:

[PDF] 211 KB (991)

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The instability and failure of strip coal pillar along strike is a typical nonlinear process. A mechanical model of strip coal pillar is established，based on which，the expression of total potential energy function is derived. Then the cusp catastrophic model for instability and failure of strip coal pillar along strike is set up by catastrophic theory. The formula of necessary and sufficient condition for instability and failure of strip coal pillar along strike is obtained according to the cusp catastrophic model. In the mean time，the effect of underground water on the coal pillar is considered in the model for the first time. The cusp catastrophic model indicates that underground water reduces the strength and the rigidity of core part of coal pillar and leads to sudden instability of coal pillar. At last，the mechanism of instability and failure for strip coal pillar along strike is analyzed according to the cusp catastrophic model. As a result，a new theoretical method of studying the instability and failure of coal pillar of strip-partial mining is put forward.

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ANALYSIS ON PARTIAL SHORT-SUPPORTING EFFECT IN
HIGH STRESS TUNNEL

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2004, 23 (12): 2001-2001 doi:

[PDF] 183 KB (927)

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The instability happens in high-stress tunnels in two cases，full supporting or short supporting. Tunnel bracing will be destroyed at the short supporting position when the rock popping-out is large enough. The short supporting is a common phenomena with lack of researching. The analysis of partial short supporting effect is studied on the basis of elastic and viscoelastic theory. The mechanism of heaving and instability of roof and side wall is analyzed. As result，a new rationale is proposed for the design of tunnel support.

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TESTING STUDY ON PERMEABILITY OF NON-DARCY FLOW IN POST-PEAK SANDSTONE

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2004, 23 (12): 2005-2005 doi:

[PDF] 212 KB (1143)

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It is of practical importance to investigate the permeability of rock under high stress，especially under post-peak stress with low confining pressure. A patented device，combined with MTS815.02 Rock Mechanics System，makes the measurement of non-Darcy permeability possible. The configuration of test system of permeability measurement of non-Darcy flow in post-failure rock，test principle and plan，and the processing method for test data are presented. The permeability of non-Darcy flow in post-peak rock is carefully measured by using steady seepage method. Sandstone specimens are divided into five groups. Every group consists of ten specimens，which undergo same axial strain before permeability measurement. The permeability of each specimen is obtained by fitting the seepage velocity-pressure gradient curve. The statistical indexes of every group of specimens are calculated. The relation between the indexes and axial strain are established by linear regression. It is shown that the permeability of post-peak rock is remarkably larger than that of pre-peak rock. The permeability of post-peak rock varies parabolically with axial strain. This study provides the method and technique for measuring permeability of non-Darcy flow in post-peak rock，which can be employed in mining，civil and other engineerings.

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STUDY ON GROUNDWATER LEAKAGE OF FOUNDATION PIT WITH TEMPERATURE TRACER METHOD

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2004, 23 (12): 2010-2010 doi:

[PDF] 188 KB (981)

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During the construction of foundation pit，some characteristic factors about groundwater seepage field，should be investigated for the dewatering，antiseepage and supporting works. Temperature is a natural tracer of groundwater movement. Normal temperature distribution of strata is continuous and regular. Under the influence point of seasonal temperature，strata temperature will increase with depth，but groundwater movement will bring abnormality to this distribution. This abnormality of temperature curve can be used to study the permeability of strata and locate the concentrated leakage passage. Related information about groundwater seepage field is provided by the abnormality of the curve of temperature vs. depth，such as the location of strong leakage layer and the relation of groundwater recharge. As an example，ground water temperature tracer detection is performed in the foundation pit of Sanshanjie Subway Station in Nanjing. The case study shows that the major reason of leakage of foundation pit is the inadequate depth of underground continuous wall and the existence of faults on the wall. Deep confined water is drained out and then this will cause the ground settlement around the foundation pit. Corresponding countermeases are proposed accordingly.

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NUMERICAL MODEL OF THREE-DIMENSIONAL DISCRETE FRACTURE NETWORK FOR SEEPAGE IN FRACTURED ROCKS
(Ⅰ)：GENERATION OF FRACTURE NETWORK

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2004, 23 (12): 2015-2015 doi:

[PDF] 276 KB (2104)

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A numerical model of three-dimensional discrete fracture networks for seepage in fractured rocks is presented. Fractures are modeled as circular or quadrangular disks with arbitrary size，orientation，location and transmissivity. A fracture network is characterized by the statistical distributions of these parameters. Based on this model，a code for predicting seepage in fractured rocks，FracFlow，is developed，which can estimate the statistical distribution of the appropriate geometric parameters through field measurements，generate statistically identical fracture network，and compute the flow responses of this fracture network. The program can also use site-specific geometric data to generate fracture network. Boundary element method is used to discretize the fracture network and solve the problem of seepage. In the first part of this paper，only the detailed process of the generation of three-dimensional stochastic fracture networks using field data is introduced. At last two samples are given for the calibration of this program.

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NUMERICAL MODEL OF THREE-DIMENSIONAL DISCRETE FRACTURE NETWORK FOR SEEPAGE IN FRACTURED ROCKS
(Ⅱ)：COMPUTATION OF STEADY FLOW

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2004, 23 (12): 2021-2021 doi:

[PDF] 249 KB (1082)

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The work of the first part of this paper is continued by describing the numerical simulation technique of steady state flow in three-dimensional artificial fracture network. Every fracture disk is taken as a two-dimensional flow domain with a uniform transmissivity，in which the flow is determined by the Laplace equation. The boundary element method is used to calculate the steady flow of single fracture. For flow between two intersecting fractures，additional internal boundary elements are introduced to represent the line of intersection between the fractures. For a network of intersecting fractures，with consideration of mass balance and equivalence of heads along the interboundaries，a large matrix can be formed. All the unknown head and fluxes can be determined by solving this matrix. In addition，the fundamental solutions of the boundary element method for the governing function of flow problem is discussed and the equivalence of three typical fundamental solutions is proved.

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3D FEM ANALYSIS OF SATURATED-UNSATURATED SEEPAGE FIELD WITH DENSELY-DISTRIBUTED DRAINAGE HOLES

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2004, 23 (12): 2027-2027 doi:

[PDF] 350 KB (980)

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To the unsaturated-saturated seepage field with densely-distributed drainage holes existing in the computational domain，the drainage substructure is introduced. The involved formulae are deduced and the computation program is developed. Meanwhile，rainfall infiltration and precise simulation of the exit face of the saturated-unsaturated seepage are also introduced. Finally，the problem of the slope seepage field of the permanent shiplock of the Three Gorges Project is calculated. The effectiveness and propriety of the seepage control measures in the slope are analyzed and verified.

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COUPLING ALGORITHM OF SIMULATED ANNEALING ALGORITHM AND RANDOM SEARCH METHOD FOR SLOPE STABILITY ANALYSIS

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2004, 23 (12): 2032-2032 doi:

[PDF] 212 KB (1095)

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For the stability analysis of slope of non-circular slip surface，any partial optimization solution is possible to overvalue the safety factor. In this paper，a general optimization model applicable to optimization analysis of slope stability under any complex conditions，including complex boundary and shape of slope surface and soil data，is firstly presented，and then a coupling algorithm of simulated annealing algorithm and random search method is introduced for giving a global search method of slope stability analysis. Such a coupling algorithm combines the merits of the two methods. Three practical examples，with minimum safety factors and associated slip surfaces known，are carefully calculated and analyzed，and the feasibility and efficiency of the proposed coupling algorithm are proved.

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DISPLACEMENT CORRECTION AND DEFORMATION FORECAST OF FOUNDATION PIT WITH FEEDFORWARD NEURAL NETWORK

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2004, 23 (12): 2038-2038 doi:

[PDF] 195 KB (1040)

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Due to the great depth，good continuity and high reliability of monitoring，bore inclinometer becomes a main monitoring measure for the deformation of foundation pit walls. In the process of field measurement with inclinometer，blocking often occurs in the bottom of inclinometer. Measured displacements can be corrected with data from some reliable points，and the displacements of blocked section may be deduced through feedforward neural network. Furthermore，the local displacements may be corrected，and the deformation trend of foundation pit walls can be forecasted with feedforward neural network.

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DETERMINING SHEAR STRENGTH FOR LANDSLIDE IN EXPANSIVE SOILS BY BACK CALCULATION WITH MULTIDIMENSIONAL CHART

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2004, 23 (12): 2042-2042 doi:

[PDF] 166 KB (859)

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Because of special mechanical characteristics of expansive soil and disturbance of sliding，it is hard to obtain the soil shear strength parameters by general shear experiments in lab. Whereas，shear strength of soil is crucial in the stability analysis of landslide. The method of back calculation with multidimensional chart is given to calculate soil shear strength of landslide in expansive soils conveniently. The validity of the method is shown by computation examples.

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FUZZY OPTIMIZATION MODEL OF SUPPORT SCHEME FOR DEEP FOUNDATION PIT AND ITS APPLICATION

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2004, 23 (12): 2046-2046 doi:

[PDF] 156 KB (1381)

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Based on the characteristics of support scheme for deep foundation pit，the objective function is constructed with theory of fuzzy mathematics and least square method. A mathematics model of fuzzy optimization of support scheme for deep foundation pit is established to offer a scientific and effective approach to the managers of civil engineering. The practical example，with 3 support schemes for deep foundation pit in Nanjing，is introduced and compared to the results obtained by other methods.

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CALCULATING SECTION SETTLEMENT OF HIGHWAY
EMBANKMENT WITH ERPIM

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2004, 23 (12): 2049-2049 doi:

[PDF] 276 KB (859)

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Meshless method，which needs no elements message but only nodal message，is more suitable to analyze geotechnical engineering problem. After the basic theory of radial point interpolation method with equal polynomial basis (ERPIM) is introduced and the main solution equations for Biot’s consolidation using meshless method are developed，the settlement of highway on soft ground is calculated with this new meshless method. The results of ERPIM are more accurate. Moreover，ERPIM is more convenient in handling the moving boundary problem such as embankment constructed by steps. Finally，the problem for further study is pointed out.

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3D FEM ANALYSIS OF SLUICE ON SUZHOU RIVER BAYOU CONSIDERING SOIL CONSOLIDATION

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2004, 23 (12): 2054-2054 doi:

[PDF] 228 KB (1037)

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Considering soil consolidation，the design of sluice on Suzhou River bayou is introduced，and the time-dependent interaction between pile，soil and structure under different operating conditions is analyzed by using 3D finite element method. Piles and structure are modeled as linear elements，and soils are modeled as nonlinear elements. Contacted interface elements are set between pile elements and soil elements. It is found that the counterforce of the piles and the settlement of the sluice raft both increase during soil consolidation. The differential settlement is very small，and the counterforce of corner piles is larger than that of middle piles. The calculation results show that the design of sluice，the model and parameters adopted for calculation are all rational.

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A NEW METHOD OF CALCULATING SETTLEMENT OF COMPOSITE
PILE FOUNDATION——MODIFIED SIMPLIFIED STRESS METHOD

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2004, 23 (12): 2059-2059 doi:

[PDF] 267 KB (948)

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On the base of theatrical analysis，experiment results and the numerical simulations，a new method of calculating the settlement of composite pile foundation—modified simplified stress method is put forwarded，and is applied to three project cases. This method takes the compress of soil between piles into account，which accords with the deformation characteristic of composite pile foundation. The comparisons of calculation results and measurement dada show that the new method enjoy the merits of simplified calculation，clear physical concept and certain precision. So it is convenient to apply the method to the practical engineering.

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PREDICTION OF RETAINING STRUCTURE DISPLACEMENT IN FOUNDATION PIT

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2004, 23 (12): 2065-2065 doi:

[PDF] 210 KB (2001)

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An approach for predicting the displacement of the retaining structure of foundation pit is proposed based on in-situ data，optimum back analysis and elastic finite element method. With the monitoring information of displacement in the process of deep excavation，the optimum back analysis is used to calculate the properties of soils and retaining structure，which are then applied to predict the displacement of the retaining structure in the next stage. The back analysis is repeated in subsequent stages until the end of excavation. The results of back analysis provide guidance on design and construction of deep excavation and assessment on the security of excavation operation.

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GRAY PREDICTION OF ULTIMATE BEARING CAPACITY OF
SINGLE PILE

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2004, 23 (12): 2069-2069 doi:

[PDF] 148 KB (953)

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It is of great significance for civil engineers to accurately predict the ultimate bearing capacity of single pile with the limited measurement data. Based on the grey theory，GM(1，1)，a grey model of load-settlement relation for single pile is established. The prediction method of ultimate bearing capacity and the whole load-settlement curve are discussed in detail. The results of engineering cases prove that this method is reliable，and the precision of prediction can meet engineering need.

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REVIEW ON LATERAL DEFORMATION EFFECTS OF EMBANKMENT ON PILED BRIDGE ABUTMENTS ON SOFT CLAY

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2004, 23 (12): 2072-2072 doi:

[PDF] 182 KB (1270)

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According to geotechnical literatures，the current research situation of embankment lateral effects on the piled bridge abutments on soft clay is analyzed. The field observation results and centrifuge model tests of piled bridge abutments on soft ground，finite element analysis of the soil-pile interaction and various computation techniques of the lateral earth pressure acting on the piles from horizontal soil movements are summarized. The existing problems and potential research topics in this field are put forward. A combined method of the finite element analysis and centrifuge model test is proposed.

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EFFECT OF PILE-SOIL-STRUCTURE INTERACTION ON DOWNWIND RESPONSE OF HIGHRISE BUILDING TO WIND-INDUCED VIBRATION

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2004, 23 (12): 2078-2078 doi:

[PDF] 271 KB (1677)

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Considering the pile-soil-structure interaction (PSSI)，the formula of the downwind displacement response is derived for highrise building subjected to fluctuating wind load. Numerical examples show that PSSI has evident effect on downwind displacement response of the building. Generally speaking，it is not always conservative to consider PSSI in the analysis of downwind responses of tall building. When the damping in the soil is small，the elastic relative displacement response of the structure considering the PSSI may be greater than that without considering the PSSI，and the total displacement response of the structure considering PSSI is always greater than that without considering PSSI，which may increase the uncomfortableness of the structure. This phenomenon becomes more significant if the building is higher. So more attention should be paid to the effect of the PSSI in the design of tall building.

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STUDY ON GROUNDWATER LEAKAGE OF FOUNDATION PIT WITH TEMPERATURE TRACER METHOD

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2004, 23 (12): 2085-2085 doi:

[PDF] 284 KB (1374)

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During the construction of foundation pit，some characteristic factors about groundwater seepage field，should be investigated for the dewatering，antiseepage and supporting works. Temperature is a natural tracer of groundwater movement. Normal temperature distribution of strata is continuous and regular. Under the influence point of seasonal temperature，strata temperature will increase with depth，but groundwater movement will bring abnormality to this distribution. This abnormality of temperature curve can be used to study the permeability of strata and locate the concentrated leakage passage. Related information about groundwater seepage field is provided by the abnormality of the curve of temperature vs. depth，such as the location of strong leakage layer and the relation of groundwater recharge. As an example，ground water temperature tracer detection is performed in the foundation pit of Sanshanjie Subway Station in Nanjing. The case study shows that the major reason of leakage of foundation pit is the inadequate depth of underground continuous wall and the existence of faults on the wall. Deep confined water is drained out and then this will cause the ground settlement around the foundation pit. Corresponding countermeases are proposed accordingly.

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APPLICATION OF ENVIRONMENTAL ISOTOPE AND HYDROCHEMISTRY TO LEAKAGE STUDY

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2004, 23 (12): 2091-2091 doi:

[PDF] 237 KB (1074)

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The theory of environmental isotope and hydrochemistry applied to leakage study is described. As natural tracers，environmental isotope and hydrochemistry mark groundwater，river water and precipitation. By contrast of the composition of environment isotope and water chemistry in water，the relation between them can be determined to distinguish the replenishment resource of groundwater，the position and range of leakage，the stratum formation and and so on. Some conclusions are drawn and also proved by other methods in three examples. So it can be concluded that environmental isotope and hydrochemistry can be used as a useful measure for dike leakage study and a guidance for dike reinforcement.

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TESTING STUDY ON ENGINEERING CHARACTERISTICS
OF PHOSPHOGYPSUM

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2004, 23 (12): 2096-2096 doi:

[PDF] 183 KB (1208)

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Based on tests of chemical composition，size grading，compaction，triaxial shearing and compression of phosphogypsum，as industrial waste，its characteristics are presented. Then the feasibility of applying phosphogypsum to the ground treatment is discussed.

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PRETENSIONED SUPPORT OF ROADWAY DRIVEN ALONG NEXT GOB AND HEADING ADAJACENT ADVANCING COAL FACE
AND ITS APPLICATION

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2004, 23 (12): 2100-2100 doi:

[PDF] 605 KB (1162)

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Identifying the movement and damage of the roof rock is important to the appropriate support design of a roadway driven along next gob and heading adjacent advancing coal face，which is under strongly dynamic pressure and severely subject to the whole breaking process of lateral main roof strata. A mechanical model of the triangle block structure for the main roof above roadway is established to elucidate that the structure can keep self-stable before and after roadway excavation. Because of the adjacent mining-induced effect，the separation of coal seam or weak rockmass from the roof and collapse of the purposely-left narrow coal pillar will unavoidably occur，the stability of the structure is lowered，and the structure must become instable with decrement of coal strength. So effective support is needed to control the separation of roof and prevent the large deformation of roadway. The conventional reinforcement for the walls and corners of roadway by bolting，metal supporting，resin anchored bolt supporting and the method of bolt combined with cable are not good enough to achieve this goal. A new pretensioned support technology is recently developed，which is a creative combination of pretensioned truss of steel strand，pretensioned cable with small borehole，high-quality bolt and M-shape steel strip. A successful application of this technology to Sanhejian coalmine of Xuzhou mining field is illustrated，and the good behavior of this technology is proved.

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STABILITY OF FRICTION-BEARING PILES

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2004, 23 (12): 2106-2106 doi:

[PDF] 235 KB (849)

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On the basis of m-method in subgrade-reaction theory，horizontal pile displacements are expressed by beam-functions，and the influence of the skin frictional resistance along the pile on stability of end-bearing pile is discussed. The effect of positive and negative skin friction on equivalent length is shown. The calculated results indicate how load transfers along the pile and the negative friction has essential influence on pile stability. So the practice of ignoring the negative friction is dangerous.

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SIMPLIFIED DESIGN METHOD OF COMPOSITE PILE FOUNDATION WITH SLEEPER

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2004, 23 (12): 2110-2110 doi:

[PDF] 210 KB (973)

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According to the design theory of composite pile foundation，the simplified design method of composite pile foundation with sleeper is presented based on the engineering practice in Nanjing. In this design theory，the ultimate bearing capacity of single pile is adopted in friction pile groups with large pile spacing and low pile cap，and the loads acting on the composite pile foundation are distinctly shared by the piles and the soil under the cap. The design method is simple，convenient and efficient with promising prospect of employment.

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TESTING STUDY ON LATERAL DEFORMATION OF SOFT ROAD GROUND AND ITS CONTROL

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2004, 23 (12): 2114-2114 doi:

[PDF] 235 KB (1054)

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The problems in measuring the lateral deformation of soft road ground with the inclinometer are analyzed. The interaction mechanism between the inclinometer and soft soil，and the calculation method of the soil displacement are discussed，considering the relative influence factors. The testing study is made in site on the lateral deformation of soft road ground，and the testing results show that quantitative research on the rational reinforcement measure for soft soil is necessary for controlling of its lateral deformation.

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APPLICATION AND DISCUSSION OF DMT

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2004, 23 (12): 2118-2118 doi:

[PDF] 315 KB (1327)

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Flat dilatometer test (DMT) procedure is introduced in detail. The field data obtained with DMT method in a case are compared with the data from other tests. According to the actual geological condition in Nanjing，several empirical formulas are suggested. And the engineering applications of DMT are discussed in some aspects.

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APPLICATION OF MEASURBLE PREFABRICATED DRAINS OF HIGH QUALITY TO IMPROVEMENT OF SOFT GROUND

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2004, 23 (12): 2123-2123 doi:

[PDF] 353 KB (1060)

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Measurable prefabricated drains of high quality are developed in recent years. The discharge capacity and the mechanical properties of these prefabricated drains are improved significantly due to easy measuring of penetrated depth in soft foundation，changing in wrapping mode of drain cores and employing of new material. Prefabricated drains are adequate to the worse construction environment and can meet the demand of higher project quality. So they are excellent and hopeful material in soil improvement.

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FIELD TESTING STUDY ON COMPOSITE SOIL NAILING

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2004, 23 (12): 2128-2128 doi:

[PDF] 265 KB (1306)

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The support system using self-drilling soil nail with sealing wall is described and applied to the foundation pit of Xuanwu Lake tunnel project. A field investigation with extensive instrumentation and data collection is carried out to monitor performance and safety of this type of composite soil nailing. From the field tests，it is found that (1) the largest horizontal deflection is at the bottom of the soil nailed structure，(2) the nail force increases rapidly during construction and remains as an almost constant thereafter，and (3) at first the nail head force decreases slightly，but then increases during construction. The behaviors of composite soil nailing during construction and in service are further investigated based on the measurements.

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ANALYSIS ON ECO-SLOPE-ENGINEERING IN EMBANKMENT ENGINEERING

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2004, 23 (12): 2133-2133 doi:

[PDF] 187 KB (1138)

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General principles of eco-slope-engineering in embankment engineering are discussed. Geomechanical effects of eco-slope-engineering are analyzed especially. The roots are taken as friction piles according to the mechanical pattern of root piles，and the constitutive model for computation of the slopes strengthened by deep-thick roots is suggested based on the mechanical equilibrium conditions. Several new techniques in this field are introduced.