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2005, 24 (20): 0-0 doi:

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ENGINEERING GEOLOGY AND ROCK MECHANICAL PROBLEMS IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3603-3603 doi:

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The first phase of west route of South-to-North Water Transfer Project consists of 4 dams，2 weirs and 7 tunnels which transfer water of 4 billion cubic meters to the Yellow River annually. The most complicated part of the project belongs to the design and construction of these long tunnels at great depths. The majority of strata lithology are Triassic sandstone and slate；and the dam condition is good. With complicated engineering geologic condition，the major existing problems include the stability of surrounding rock passing through shattered zone，high geostress and high geo-temperature of deeply bedded tunnels，inrush of water，and the slope stability of tunnel¢s intake. These complex engineering geologic problems can be solved. The geological condition is feasible. The elevation of the project varies from 3 400 m to 4 800 m，where oxygen is in shortage and heavy physical labor is not applicable. So TBM method is acceptable，whose double protection shields are adopted for excavation in the project.

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EVALUATIONS FOR HYDROGEOLOGICAL CONDITIONS ALONG WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3614-3614 doi:

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In the region of the west route of South-to-North Water Transfer Project in China，the topographical，geological and climatic conditions are very complicated and the field investigations are also very difficult to be performed. With the consideration of the above reasons and limit research time，an integrated evaluation method is developed to study the related hydrogeological conditions of the region，in which the remote sensing technique is mainly adopted with combination of field ground surface investigation，environmental isotope research，field data analysis of borehole water pressure test and isotope trace test，hydrogeochemical analysis of groundwater from springs，and numerical modeling，etc.. The hydrogeological conditions of west route region in the South-to-North Water Transfer Project are also studied，such as the major types of groundwater and the geochemical properties，the spatial distribution of main aquifers，the main hydrogeological elements and the relations among supply- runoff-drainage，groundwater movement，etc.. There are two main aquifers in the region：the pore aquifer and the weathered fracture aquifer with a large groundwater runoff intensity caused by physical weathering process. It is the basic hydrological characteristics that there is an active deep groundwater cycle through tectonic fractures and faults with rich water storage. Considering the application to the hydraulic engineering，the hydrogeological parameters are also investigated. The possible water quantities flowing into tunnel are finally studied；and the possible hydrogeological problems of the engineering are presented. The water flow from rock mass into tunnel will be the main hydrogeological problem. The research also provides a new way to evaluate the hydrogeological conditions for the region covered by high mountains.

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STUDY ON IN-SITU STRESS MEASUREMENTS AND CHARACTERISTICS OF IN-SITU STRESS FIELD IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3620-3620 doi:

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The following preliminary results are obtained based on in-situ stress measurement in the west route area of South-to-North Water Transfer Project of China by using hydraulic fracturing (HF) method：(1) the largest amplitude of maximum horizontal principal stress in all the boreholes along the water transfer route is about 25 MPa with the orientation of NNE or NEE；(2) the largest amplitude of maximum horizontal principal stress is about 17 MPa in all the boreholes in the dams areas，and the orientations are mainly NNE or NEE though influenced by local topography；(3) the ratio of lateral pressure decreases with the increasing depth in all boreholes along the water transfer route. When the depth is greater than 200 m from the ground surface，the ratio is close to 2；(4) the ratios of lateral pressure in all boreholes are greater than 1，which implies that the tectonic stresses in this area are dominant；(5) the magnitudes of the maximum and minor horizontal principal stresses increase with the increasing depth of boreholes；(6) the fine linear relationship between the magnitude of maximum horizontal principal stress and borehole depth in all boreholes along the water transfer route is observed based on regression analysis；and (7) medium rock burst or rheology is likely to be induced by the high stress in the deeply buried long tunnels.

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CLASSIFICATION AND DEFORMATION ANALYSIS OF TUNNEL SURROUNDING ROCK IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3625-3625 doi:

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According to the engineering geological conditions and the proportions of the sandstone and the slate，the strata in the tunnel area are divided into different parts. The rock mass and the structural planes are classified into different species. The rock near the tunnel is then classified using the T system and the RMR system. The deformation of surrounding rock is calculated and analyzed according to the Hoek-Brown method based on the geological strength index(GSI). By classifying the surrounding rock and calculating the deformation，the tunnel boring machine(TBM) applicability in the west route of South-to-North Water Transfer Project is discussed.

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GEOPHYSICAL EXPLORATION OVER LONG DEEP TUNNEL FOR WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3631-3631 doi:

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Geophysical exploration is conducted with controlled source audio magnetic telluric(CSAMT) method which is the main exploration method，VLF method，IP and TEM for some stations for the long deep-lying tunnel with a length of 20 km in west route of South-to-North Water Transfer Project. The exploration results with these four geophysical methods are introduced. According to the geophysical and engineering geological exploration results，the geological structure characteristics for the surrounding rock of the long deep-lying tunnel are interpreted；and the faults，fractures and some anomalies that may cause danger to the tunnel construction are explained.

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EXPERIMENTAL STUDY ON THERMO-MECHANICAL AND HYDRO-MECHANICAL COUPLING OF SANDSTONE FOR WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3639-3639 doi:

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Based on the condition of the west route of South-to-North Water Transfer Project in China，the triaxial compression tests under confining pressures (from 0 to 60 MPa) coupled with temperatures (form 20 ℃ to 70 ℃) as well as confining pressures (from 25 to 60 MPa) coupled with pore water pressure (from 0 to 10 MPa)have been conducted on sandstone specimens. The results show that，at the same temperature，the strength of the rock increases with the confining pressure；but the deformation modulus doesn¢t change distinctly with confining pressures. The influence of temperature on the strength and deformation properties is complex. The strength increases with the temperature when the confining pressure is lower than 40 MPa；whereas，when the confining pressure is greater than 40 MPa，the strength tends to decrease with the increasing temperature. It is also indicated that the deformation moduli generally increase with the increasing temperature. Under the condition of pore water pressure，it is shown that the strength of the rock increases with increasing of confining pressure and pore water pressure，and the deformation moduli of the rock increase with the increasing confining pressure and decrease with the increasing pore pressure.

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NUMERICAL SIMULATION ON FAULT DISPLACEMENT CHANGING WITH DEPTH IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3646-3646 doi:

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3D elastic finite element method is used to study the fracture displacement of site in the west route of the South-to-North Water Transfer Project. By simulating the displacements of faults with different widths and elastic moduli，it is showed that the horizontal fault displacement's rising rate is smaller than that of the vertical fault at 1 000 m under the ground. Keeping the other parameters constant，the rising rate of the fault slipping displacement is the same as the calculated value using different epicenter fracture lengths. The study of the present work can be a good reference to the engineering practice.

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STUDY ON EFFECTS OF DISCONTINUITIES ON MECHANICAL CHARACTERS OF SLATE

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2005, 24 (20): 3651-3651 doi:

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Single discontinuity theory is used to analyze the change of rock mass strength with the discontinuity inclinations；and the relationship between them is set up to explain the compression results. Then the results are used to the slates from the engineering of the west route of South-to-North Water Transfer Project，and the modeling results accord with the experiment ones. Some conclusions are drawn from the analysis as follows：(1) the single discontinuity theory can explain the phenomena of uniaxial and triaxial compression test on the slates；and the results can be used to the engineering；(2) the compression strength gets the minimal value when the discontinuity inclination is 51.7°；then it will increase towards two sides till reaching to the intact rock mass strength；(3) the deformation forms change with the different discontinuity inclinations，and the specimen can be damaged by sliding along discontinuities，shear failure and the combination of the two modes；and (4) the failure mode changes from the combined failure to shear failure when the confining pressure increases. The increment of the discontinuities number brings little effects to the rock mass strength.

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TECTONIC STABILITY ANALYSIS FOR WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3657-3657 doi:

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The west route of the South-to-North Water Transfer Project is planned to transit water by means of long deep-lying tunnels across the Bayanhar Mountain. The key engineering geological problems affecting the safety of the water diversion project are the fault activity and earthquake. The tectonic stability is discussed in this paper. The regional tectonic activity does not affect seriously the safety of water transfer project.

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ACTIVE TECTONICS ALONG SITE AND NEIGHBORHOOD OF WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT IN CHINA

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2005, 24 (20): 3664-3664 doi:

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The first stage project of the west route of South-to-North Water Transfer Project is located in Bayankela block interior of the eastern Qinghai—Tibet Plateau. The boundary of Bayankela block is all the giant strike-slip or thrust fault systems，which have intense activity；and the boundary belts are the primary sites of the accumulation and release of stress resulted from the blocks movement. The fault activity is weaker in Bayankela block interior than that of the boundary belts. Partial faults of Gande—Aba fault system，Seda—Luoruo fault，and Kangle fault，etc.，were active at one time since Late Pleistocene epoch. However，they have weaker active intensity than the boundary belt. The average displacement rates of the block boundary faults in the late Quaternary Period were generally more than 7 mm/a；the maximum value was up to 18 mm/a，and the minimum one was 1-2 mm/a；however，the slip rate of the most primary active fault at the raceway vicinity is only 0.18 mm/a. In general，the crust of the project site is relative stable. The maximum dip-offset of the faults needed to be protected for the project during useful life has been deduced；for example，for the Aba basin north marginal fault and the Shunhe fault the maximum value is 0.67 m and 2.62 m，respectively.

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GROUNDWATER RUNOFF MODULUS，ROCK PERMEABILITY AND PREDICTION OF WATER QUANTITIES OF TUNNEL IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3673-3673 doi:

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Based on the analysis of topographic and geological conditions along the west route of South-to-North Water Transfer Project，the groundwater runoff modulus and the rock permeability properties are studied. Firstly，an integrated method for evaluating groundwater runoff modulus of non-karst plateau region is presented，in which the hydrological map analysis is mainly applied，combined with remote sensing interpretation and the analysis of field flow data obtained from the survey of regional springs and streams. In the analysis of hydrological map，it is emphasized that the influences of rainfall and snow melting should be considered during map being cut. In the calculation of groundwater runoff modulus according to field survey data of stream flow，a seasonal reduction coefficient is proposed. The research results indicate that the groundwater runoff modulus within the hydrogeological element of Jiaqu River is largest whereas those in the other elements have similar values. Secondly，the permeability of rock mass is also studied in terms of data analysis of field water pressure test and isotope trace test. In dealing with test data，a method of omitting unreasonable data is suggested，because these kinds of data are possibly caused by poor seal of orifice or by the occurrence of the faults passed across borehole. A negative exponential relationship describing the permeability variation with depth is developed. The results of the above parameters are finally applied to the prediction of water quantities flowing into tunnel.

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NUMERICAL ANALYSIS OF SEGMENT LININGS IN DEEP AND LONG TUNNELS OF WEST ROUTE OF SOUTH-TO-NORTH WATER
TRANSFER PROJECT

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2005, 24 (20): 3679-3679 doi:

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In-situ stress and groundwater have important influences upon the design and construction of the lining for deep and long tunnels. The mechanical properties of segment linings for deep and long tunnels of west route of South-to-North Water Transfer Project are analyzed by using numerical simulation method. The influence of surrounding rock deformation and water pressure on the segment linings is studied. The preliminary results show that the segment linings can be used in approximate 90% segment of the tunnel as the surrounding rock has a good stability and the deformation has less influence upon segment linings. The external water pressure is very high around the tunnel，which is the main factor affecting the design of tunnel lining. The measures of high-pressure concrete grouting should be applied to decrease the external water pressure. The results can provide a basis for the design of linings in the first phase of the west route of South-to-North Water Transfer Project.

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PRELIMINARY REMOTE SENSING EVALUATION ON REGIONAL STRUCTURAL STABILITY IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3685-3685 doi:

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According to the interpretation marks of active faults and ring-shaped structures and the results of the field survey，about 200 faults and 26 ring-shaped structures were determined. Fault structures strike northwest，northeast，south-north and east-west，respectively；and the faults which strike northwest are regional faults and have controlled the development of geomorphology and river system in the project area. There are 22 faults whose linear features in remote sensing images are more obvious and scales are larger in all faults. Among them，8 regional or main faults have relatively larger effects on the stability of water transfer project. However，it has been stated clearly by synthetical analyses that，although 2 faults among 8 larger-scale faults have obvious active signs since Holecene，they don¢t pass through the water transfer route and even if the other 7 faults cut through the water transfer route，they don¢t have evident active marks since late Quaternary，so they don¢t have critical threat on project stability. It has also been shown that the project area lies in a relatively safe island through regional geological structural analysis. Most ring-shaped structures were formed by magmatism and can improve the project stability to some extent. Four dam areas including Ada，A¢an，Shangduke and Ya¢ertang dams are still in the structural stable period at present. In short，the project of the west route of South-to-North Water Transfer Project can be carried out.

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RESEARCH ON DEBRIS FLOW AND OTHER MOUNTAINOUS HAZARDS IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

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2005, 24 (20): 3691-3691 doi:

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The west route of South-to-North Water Transfer Project China lies in the east of Qinghai—Tibet Plateau. This area belongs to mountain-hazard-prone area due to the natural conditions of the special geology，landform，soil，vegetation，weather，hydrology and so on. Collapse，landslide，debris flow and other mountainous hazards are well developed，which are influenced and controlled by the natural factors and human activities. The main mountainous hazards are landslide，collapse，debris flow，dangerous slope，large-scale deposit. The secondary hazards are mountain torrents，water loss and soil erosion，freezing and thawing solifluction，road foundation collapse and so on. The distribution characteristics，rules and the status of other mountainous hazards are found out in west route of South-to-North Water Transfer Project through field survey，topography map implement，GPS fixed-point，aerial photos and TM，SPOT satellite image interpretation. The bursting scales of debris flow (the maximal flow，the total amount of a debris flow) are analyzed and predicted. The blockage of the river by debris flow (possible height，backwater length) and the quantitative analysis methods of the second possible hazards derived from debris flow are discussed. On the basis of the analysis，the possible influence of the mountainous hazards on the west route of South-to-North Water Transfer Project is considered；and the probable dangers are presented.

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SOME ESSENTIAL CONSIDERATIONS OF ROCK MECHANICS IN HYDRAULIC ENGINEERINGS

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2005, 24 (20): 3696-3696 doi:

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Based on the experience of rock mechanics study accumulated in the past 50 years in the fields of hydraulic and hydropower engineerings，some essential considerations including the purposes and the distinctive characteristics of these studies are studied. It is emphasized that the three parts of rock mechanics study in hydraulic engineerings，i.e.，reconnaissance of rock mass，utilization of rock mass and reinforcement of rock mass，are closely related to each other. In addition，some attitudes associated with rock mechanics study in hydraulic engineering in aspects of uncertainties of rock mass and the corresponding strategies，phasic problems in rock mechanics study，the main contents of rock mechanics study，characteristics related to the three kinds of rock engineerings(dam，rock slope，and underground openings)，relationship with engineering geology and engineering design actual behavior monitoring of engineering rock mass，and general comments considering the environmental protection and the maintenance of ecological equilibrium are presented and summarized.

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REINFORCEMENT THEORY CONSIDERING DEFORMATION
MECHANISM OF ROCK MASS AND NON-EQULIBRIEM ELASTO-PLASTIC MECHANICS

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2005, 24 (20): 3704-3704 doi:

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The reinforcement theory considering deformation mechanism of rock mass is proposed and authors. The main ingredient of the theory is that the unbalanced forces of a deformable body in elasto-plastic elaborated. calculation are just the required reinforcement forces，and the elasto-plastic calculation always tends to minimize the unbalanced forces. It is revealed that the reinforcement theory is based on the so-called non-equilibrium elasto-plastic mechanics，which leads to the minimum plastic complementary energy principle for the corresponding unstable structures. Case study on an arch dam shows that the distribution of unbalanced force is helpful to evaluate the structural stability and reinforcement.

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FINITE ELEMENT ANALYSIS OF SEISMIC CONCRETE DAM-FOUNDATION ROCK INTERACTION IN TIME DOMAIN

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2005, 24 (20): 3713-3713 doi:

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The seismic response analysis of concrete dam is a critical step in evaluating safe performance of proposed and existing dams. The seismic response of concrete dam is substantially affected by the dynamic interaction between the dam and the foundation rock. Therefore，it is necessary to develop a numerical method including dam-foundation rock interaction in the procedure. Among various numerical methods，the finite element method is very attractive since it can be applied to any geometry for any set of material properties and loading conditions as long as the appropriate constitutive relationships and equilibrium conditions are met. In this study，a time-domain finite element method (FEM) for analysis of dynamic responses of concrete dam-foundation rock system subjected to earthquake is presented. During such FEM simulation，the disturbances due to the interaction between the dam and the foundation rock will travel outwards. An effective artificial boundary condition will limit the region for which a solution must be computed. Without such an artificial boundary condition，wave energy will reflect off the edge of the computational region and contaminate the solution. In addition，how to treat seismic input on such a artificial boundary is another key issue in the seismic response analysis of concrete dam. Based on the cylindrical wave equation，a method for treatment of earthquake input and modeling radiation damping is established，it is simple and efficient. Several numerical examples are conducted to verify the validity and accuracy of the proposed method. Finally，the proposed FEM is applied to seismic response analysis of concrete gravity dam including dam-foundation rock interaction；and the results show that the seismic response of concrete dam is substantially affected by the radiation damping of unbounded foundation rock.

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EXPERIMENTAL STUDY ON TENSILE MECHANICAL PROPERTIES OF
GLASS FIBER REINFORCED PLASTIC REBAR

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2005, 24 (20): 3719-3719 doi:

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The glass fiber reinforced plastic(GFRP) rebar is a kind of material formed with resin and glass fiber compound，with good mechanical properties and excellent corrosion resistance. The problem of durability of concrete can be solved if steel bars are substituted with GFRP rebar. Because GFRP rebar is easy to fracture，the chuck of testing machine can not hold big diameter sample，and the direct tensile test is difficult to perform. The commonly used method is processing into the small diameter sample and carrying on the test. Different diameter samples f 10，f 13，f 15 are tested；then the regression analysis for forecasting the mechanical properties of big diameter sample f 32 is implemented to avoid the influence caused by processed samples. The tensile test of the GFRP rebar is carried out；and the stress-strain curve and the failure modes of GFRP rebar are discussed. High strength and brittle failure are the most characters of GFRP rebar；and the stress-strain curve of GFRP rebar is found to be linear. Compared with the mechanical properties and prices between GFRP rebar and ribbed steel bars，the good mechanical properties and high performance/cost ratio of GFRP rebar can be testified. Meanwhile，the high strength of GFRP rebar and the good distortion coordination with concrete are testified. GFRP rebar can be used for slope engineering reinforcement in practice.

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NUMERICAL ANALYSIS OF ANCHORAGE BEHAVIOR OF FIBER REINFORCED PLASTIC BOLTS

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2005, 24 (20): 3724-3724 doi:

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Based on the theoretical differential equations of fiber reinforced plastic (FRP) bolts anchored in the rock，and combined with the continuous smooth bond-slip curve of FRP，the nonlinear numerical calculation method is put forward. The concerned parameters can be determined by comparing the calculating results with those of anchorage behavior tests. Moreover，the numerical simulation results are contrasted with the theoretical ones，and the validity of the numerical simulation method is testified.

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STABILITY ANALYSIS OF SURROUNDING ROCK OF UNDERGROUND EXCAVATIONS AND VISUALIZATION OF ITS RESULTS

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2005, 24 (20): 3730-3730 doi:

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The stability of large-scale excavations always is a key problem in underground water power stations. In order to evaluate the stability of these excavations，the three-dimensional nonlinear finite element method is used usually. The basic ideas about how to use finite element method in stability analysis of underground excavations are introduced，including the choice of constitutive relation of rock mass，iterative method of nonlinear computation，failure criterion of surrounding rock，optimal ways of stability evaluation and simulation methods of anchorage supporting structure. To realize the visualization of results of computation，visualization software of underground excavations¢ finite element analysis is developed based on the object-oriented idea. This software can draw conveniently spatial contours and vector diagram of every physical quantity and display structure¢s deformation and the distribution condition of failure area. Besides，the software can also show anchorage structure including anchor rod and anchorage cable and its stress. At last，above calculation methods and visualization software are used in an engineering example. The results show that the calculation methods presented above are rational and effective；and the visualization software is powerful in evaluation of computation results.

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APPLICATION OF EVALUATION OF ROCK MASS QUALITY TO ACCEPTANCE OF TOE-SLAB OF SHUIBUYA CONCRETE FACED ROCKFILL DAM ON QINGJIANG RIVER

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2005, 24 (20): 3737-3737 doi:

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Shuibuya concrete faced rock-fill dam(CFRD) with a height of 233 m on Qingjiang River is the highest CFRD in the world at present. The foundation rock under toe-slab has complicated lithological condition，and the rock masses are soft layers alternating with hard layers. It is worth to study that how to establish the utilizable and acceptable criteria of foundation rock with consideration of economy and engineering safety. In the past，the weathering degree or sonic wave velocity of rock mass was often used as the acceptance criterion for the utilization and caving of the rock foundation of hydraulic structure；but these criteria cann¢t reflect the comprehensive characteristics of rock masses，such as the compressive strength，deformation properties and anti-permeability of rock mass. The engineering classification of rock masses is used for evaluating the quality of foundation rock under toe-slab；and the corresponding criteria of rock utilization and acceptance are established，which are applied to the acceptance of foundation rock under toe-slab. The quality of foundation rock under toe-slab is evaluated and divided by using elastic wave and compression tests in laboratory；and the distribution of rock masses with poor quality is pointed out，which can be remedied timely during construction process.

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RESEARCH ON PROTECTIVE STRUCTURES FOR HIGH SLOPES ROCKFALL AROUND A HYDROPOWER STATION

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2005, 24 (20): 3742-3742 doi:

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Kinematics combined with probabilistic and statistic analysis is adopted to calculate kinematic energy and bounce height，which are the control factors for designing rockfall protective structures. Both rotational kinematic energy and translational kinematic energy are calculated by kinematics. The non-determinacy of falling rocks is an important specialty of rockfall. This is analogized by probabilistic analysis by altering calculating parameters in a certain range. Then，the results changes accordingly in a range，and are studied by statistic analysis. Because the slopes around the switch station for Baoquan pumped-storage power station are steep and high，this switch station is recommended to be relocated to avoid the most dangerous location where may encounter with rockfalls. But rockfalls may happen in the new area，too. So，protective structures should be built for the switch station. Based on the high rock slopes at back of the switch station，according to historical rockfall，experimental research and empirical parameter values from other projects，two-dimensional calculating cross-sections，parameters and size of rocks that may fall are determined. Computing models are established according to the practice by above-mentioned method of kinematics combined with statistics and probabilities. Based on these models，protective structures are discussed. To deal with the rockfalls that may happen in this area and to protect the switch station，a protective one of retaining walls and another plan with both active protective methods and soft protective nets are both in consideration. According to the calculated results，the two plans are compared and the plans should be chosen both by economic and technical considerations.

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DEFORMATION AND GEOSTRESS CHANGE CHARACTERIZATION OF DEEP ROCKMASS OF PERMANENT SHIPLOCK SLOPE FOR THE THREE GORGES PROJECT

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2005, 24 (20): 3749-3749 doi:

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With the purpose of acquiring rockmass deformation and geostress change characterization on the permanent shiplock slope of the Three Gorges Project (TGP)，the original exploratory adit of No.8，which was intersected with the middle-isolated pier of the permanent shiplock slope，was utilized to be a place for installing multi-point borehole extensometers(MPBX) and geostress change sensors；and the whole process of rockmass deformation monitoring for the middle-isolated pier has lasted nearly 10 years in company with 3 years geostress change monitoring. On the basis of results of deep rockmass deformation monitoring，rockmass deformation characterization of the middle-isolated pier is investigated during construction period and navigation period；and the deformation tendency of rock wall of the middle-isolated pier is obtained；in addition，results of in-situ geostress change monitoring，numerical modeling results by FEM and back analysis results based on MPBX data are compared and analyzed. The stability of the permanent shiplock slope is discussed at last.

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ROCKBOLTS SIMULATION BY NUMERICAL MANIFOLD METHOD AND ITS PRELIMINARY APPLICATION

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2005, 24 (20): 3754-3754 doi:

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According to the rock reinforcement in geotechnical engineering，the study on rock anchorage simulation by numerical manifold method (NMM) has been conducted；and the corresponding numerical simulation blocks have been compiled on the basis of the original code. Two examples are used to validate the correctness of the newly developed model. Based on the works accomplished above，the excavation of an underground opening with laminated surrounding rock mass is simulated by NMM；and the deformation characteristics are analyzed. The results show that the displacements on the two sides of the weak planes in the upper part of the surrounding walls behave discontinuously，which are reasonable compared to the actual situation. When the surrounding rock is reinforced，its displacement tends to be more uniform，and decreases to some extend. On the two sides of the weak plane the discontinuous deformation of the surrounding rock decreases more distinctly.

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EXPERIMENTAL RESEARCH ON ROCKMASS ELASTICITY RESISTING COEFFICIENT IN YANTAN HYDROPOWER STATION

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2005, 24 (20): 3761-3761 doi:

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The experiment on the elasticity resisting coefficient of rock mass is very difficult to be done，so it is conducted only in the pressure tunnel of oversize hydroelectric projects. Radial hydraulic pressure pillow testing is a kind of method to measure the rock mass elasticity resisting coefficient. It was adopted in projects such as Yingxiuwan，Qingjiang，Ertan，etc.，during the 1960¢s and 1970¢s and only the relative deformation in diameter direction is needed to be measured. It is adopted in Yantan Hydropower Station to research rock elasticity resisting coefficient by measuring radial deformation. The results reflect the superposition and anisotropy of deformation and indicate the relationship between the elasticity resisting coefficient and pressure coefficient. The test provides valuable data for the practical projects.

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INVERSE ANALYSIS OF SEEPAGE PARAMETERS FOR DAM FUNDATION OF A HYDROPOWER STATION

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2005, 24 (20): 3766-3766 doi:

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According to the engineering geology and the hydrogeology of a certain hydropower station，a finite element model with 8 geological layers and complicated boundary condition is built. The experimental results of drilling test，the pumping well test and the injection test are collected and selected as the reference points in the process of inverse analysis. The inverse analysis result shows that it is in good agreement with the experimental result at the reference points. The permeability coefficients for each geological layer and region are obtained；and the seepage field of the whole foundation of the dam has also been calculated. All of these provide the fundamental parameters for the design of dam or further analysis to check the rationality of the engineering design.

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EFFECT OF GEOMETRIC WAVE SHAPE OF ANCHOR CABLE BOREHOLE WALL ON ITS BEARING CAPACITY

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2005, 24 (20): 3771-3771 doi:

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In the pullout test of the peak shear strength between the grout and the bore wall in the interior bond section of prestressed anchor cable，it is observed that the specimen is instantly cracked by the hoop tension which is result of the geometric wave shape of borehole wall when the specimen is subjected to axial tension. The reason of this phenomenon is analyzed；and it is pointed out that the geometric wave shape of borehole wall，the tiny change in aperture of borehole，and the tortuous axis of cable are the main reasons of the phenomena. The geometric wave shapes of borehole wall in granite，gritstone and limestone are measured and presented. The effects of the geometric wave shape of anchor cable borehole wall on the bearing capacity of anchor cable are analyzed. Finally，it is found that the remote change in aperture of borehole，and the tortuous axis of cable have greater effects on numerical calculation. Because the effect is very obvious，it should be taken into account in anchoring project.

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STABILITY ANALYSIS AND SUPPORTING DESIGN OF SURROUNDING ROCKS OF DIVERSION TUNNEL FOR JINPING HYDROPOWER STATION

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2005, 24 (20): 3777-3777 doi:

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The diversion tunnel for Jinping Hydropower Station is located in the region with high mountainan and great gorge. The surrounding rockmasses of the tunnel are of deep embedded depth，long length and high ground stress. The problems of high stress and high external water pressure are prominent. Based on the design principle that the surrounding rockmass can be regarded as the main supporting structure for underground projects，this paper analyzes the deformation，stress distribution and plastic zone of the surrounding rockmass during the processes of excavation and supporting of the power tunnel for Jinping Hydropower Station project by using elastoplastic FEM. The influence of different seepage control schemes on the working behaviors of the liner and surrounding rock is studied comparatively. According to the numerical results，suggestions for supporting design of diversion tunnel with high groundwater level and deep embedded depth are proposed.

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DEFORMATION MONITORING AND STABILITY ANALYSIS OF DABAN DIVERSION TUNNEL PROJECT

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2005, 24 (20): 3783-3783 doi:

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All the comparative projects of diversion tunnel line in “nine-nine” Daban area are all through mid and lower Pleistocene strata in the Quaternary. For the granular structure of Quaternary strata，unified classification standard and method have not been established in China at present. The tunneling conditions in these strata play a dominant role in the choice of the design scheme. Therefore，the prototype examination holes are arranged on the top of the lower Pleistocene strata，which have relatively poorer tunneling conditions at the tunnel entry. Based on the monitoring of overall process of excavation and deformation after excavation for the prototype examination holes，the stability and deformation characteristics of the surrounding rock of tunnel are studied；and the result offers a scientific reference to the design and supporting of tunnel.

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STABILITY ANALYSIS OF UNSATURATED SOIL SLOPE OF LEVEE
FOR THE YELLOW RIVER LOWER REACHES

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2005, 24 (20): 3788-3788 doi:

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The triaxial test instrument for unsaturated soil controlled by stress and strain is used to measure the substrate suction and volumetric water content of unsaturated soil. The permeability coefficient of the unsaturated soil can be got from the concrete form of the Mualem equation which is deduced based on the relation between the soil-water characteristic curve equation and the permeability. The cohesive strength，internal friction angle and the internal friction angle changing with suction can be also got from the triaxial test on unsaturated soil in the laboratory. With the finite element method，the characteristics of the seepage field in the Yellow River lower reaches which is a representative unsaturated slope under the rainfall and flood condition are analyzed systematically. Also the safety factors influenced by the seepage field of unsaturated soils under the rainfall and flood are analyzed with the method of GLE which is a kind of limit equilibrium method not considering the effect of scour. The factors including the intensity of the rainfall，the permeability coefficient and the duration of rainfall and flood and the relationship between them are significant for the computation. By analyzing，the corporate influences of rainfall and flood infiltration on the safety of slope stability are analyzed；and the results show that the effect of rainfall and flood is complex and important for the safety of the river levee. The conclusions drawn from the study on the Yellow River lower levee during the rain and flood have practical significances for the hydraulic engineering.

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STUDY ON MECHANISM OF ROCK BURST BY ACOUSITC
EMISSION TESTING

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2005, 24 (20): 3796-3796 doi:

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A detailed experimental research on the mechanism of rock burst of rock with varied properties was conducted by testing technique of acoustic emission (AE) under uniaxial and triaxial stress conditions. The results of research indicate that the characteristics of acoustic emission of rock with different properties，structures，and strengths are obviously different under uniaxial conditions from those under triaxial stress conditions. But those of rocks with same property are very similar，and a regular relation is found between the special stress values of acoustic emission under two types of stress conditions in the rocks with high and lower strengthes. According to the research results，several types of rock burst is generalized，i. e.，very strong，strong，middle，weak or so，and so on. First，for some types of rocks with high strength and many tiny cracks just like granite，many centralized AE signals with high frequeny can be got from the compressive test，so the rock burst intensity level of this kind of rock can be classified as middle one. Second，for the rock with high strength and some tiny cracks just like porphyrite，AE signals can only be achieved on the high stress level from the compressison test，so the rock burst intensity level of this kind of rocks can be classified as strong one. Third，for the compact basalt with high strength and few tiny cracks，and the kinds of other rock with the similar structure and mineral，AE signals usually can be found when compression the stress is over 90% of the uniaxial compressive strength of rock；the rock burst intensity level of this kink of rock can be classified as very strong one. Fourth，for the most sedimentary rock with many cracks and pores and middle strength，just like sand rock and conglomerate，the character of AE is that the initial signals usually can be got under the lower compressive stress level；and the frequeny is too lower. So the rock burst intensity level of this kink of rock can be classified as weak or so. From the above-mentioned，another conclusion can be got that testing technique of rock acoustic emission is a scientific and effective method to track the developing procedure of rock burst and to research the mechanicsm of rock burst.