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2004, 23 (03): 0-0 doi:

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INTEGRATION OF CONVENTIONAL INSTRUMENTS AND GPS FOR REMOTE AUTOMATIC MONITORING OF SLOPES

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2004, 23 (03): 357-357 doi:

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This paper introduces the development and application of an integrated automatic slope monitoring system. The system combines (a) advanced conventional instruments and (b) accurate global positioning instruments. The development includes selection of all instruments，technical requirements，integration method and post-process of monitoring data，etc. This system has been installed in a real loose fill slope to verify its functions and reliability of the integrated system including remote data acquisition. Preliminary monitoring data are presented and discussed in this paper.

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TRIAXIAL TEST OF UNDISTURBED COMPLETELY DECOMPOSED GRANITE UNDER CT MONITORING

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2004, 23 (03): 365-365 doi:

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In this paper，the change and failure are monitored and analyzed of the structures of completely decomposed granite from Hong Kong by CU triaxial tests. The CT scanner and the new triaxial apparatus that can monitor the pore water pressure and control the drainage condition are adopted in the test. The confining pressure of two cylinder specimens is 150 and 300 kPa，respectively. To 4 cross sections of each specimen，scanning is performed at 7 stages，i.e. initial state，after consolidation，and five stages of shearing process.
Stress-strain curves and outlook change of specimens after test show that specimen failure is of different features according to different confining pressure and initial structures. Under higher confining pressure，shear failure occurs and under lower confining pressure creep failure occurs.
The CT images and CT values are discussed. Five conclusions are gained. (1) The initial structures are extremely inhomogeneous. (2) The pore is compressed and the specimens are densitified after consolidation. (3) The meso-damage is in the form of hole-crack-hole due to the structure of soils and confining pressure. (4) Soil is of a very long plastic strain stage prior to peak value and the crack propagates along the failure plane. (5) Residual strength (creep) stage is steady and lots of hole-failure appear in the soil.
In addition，a normal CU triaxial test is performed with one specimen from the same block. The results of CT triaxial tests agree well with those of normal triaxial test.

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DEVELOPMENT AND APPLICATION OF MULTIFUNCTIONAL APPARATUS FOR GEOTECHNICAL ENGINEERING
MODEL TESTS

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2004, 23 (03): 372-372 doi:

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Multifunctional apparatus for geotechnical engineering model tests consists of the main engine and accessory devices. The apparatus possesses six functions，i. e. carrying out geomechanics model tests on the single opening，caverns，slopes and foundation ditches，carrying out shear strength tests on the analogy sample of rock mass reinforced by prestressed anchor cables，and carrying out bending strength tests on concrete and reinforced concrete beam. The apparatus can rotate model in two directions，i. e. 360 degrees rounding its rotation axis and 35 degrees in a straight plane. The apparatus adopts about 10 piston-type uniform pressure loaders successfully to make a large uniform strain field in the model of openings and non-uniform range merely within 10 cm distance to the boundary of model. It also can apply uniformly distributed load or ladder type load to the boundary of the model with different lateral pressure coefficients，to obtain quasi-plane strain conditions and give the whole process curves of t-u in the shearing test. The apparatus has been used to carry out six engineering tests and the test results are all satisfactory. The presented apparatus is of wide utilizable prospect in large-scale model tests for the research and design of national defence projects，civil defences and other civil projects in the future.

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ANALYSIS ON RELATION BETWEEN SNAP-BACK OF SPECIMEN AND SNAP-BACK OF SYSTEM COMPOSED OF DIRECT SHEAR
TESTING MACHINE AND SPECIMEN

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2004, 23 (03): 379-379 doi:

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Snap-back instability of rock specimen and testing machine–specimen system are investigated. The direct shear testing machine is simplified as a steel block with certain length and elastic shear modulus. Based on gradient-dependent plasticity，the localized shear band is initiated at peak shear stress and a closed-form analytical solution on shear stress-shear strain curve in strain-softening stage is proposed. If the length of block is zero，the simplified solution can be applied to rock specimen subjected to direct shear. If snap-back of the system occurs， the structural response of the specimen is uncertain (namely，both snap-back and snap-through are possible). When the ratio of length-to-shear elastic modulus increases，the system can lose its stability easily. For the larger ratio， though snap-back of the specimen does not occur，the system will be unstable certainly. But，for the lower ratio， only if the specimen exhibits snap-back，snap-back of the system is possible. Besides，the snap-back of a specimen must lead to snap-back instability of the system. If snap-back is impossible for the specimen，both snap-back instability and snap-through are possible for the system. Some experimental results on rock failure are explained based on the presented theoretical analysis，though the experimental results seem difficult in understanding.

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DETERMINATION OF MODE-I ROCK FRACTURE TOUGHNESS WITH CRACKED CHEVRON NOTCHED BRAZILIAN DISC (CCNBD) AND APPLICATION OF SIZE EFFECT LAW

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2004, 23 (03): 383-383 doi:

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International Society for Rock Mechanics (ISRM) proposed two suggested methods for determining rock fracture toughness in 1988 and 1995，respectively. Cracked chevron notched Brazilian disc (CCNBD) suggested by ISRM in 1995 still waits for being perfected. In view of it，two types of marbles are used to make CCNBD and chevron bend (CB) specimen suggested by ISRM in 1988. These specimens are tested on the test machine of MTS810 model. The results of the tests show that fracture toughness value calculated with ISRM suggested method in 1995 is lower than that in 1988，and that fracture toughness value calculated with ISRM suggested method in 1995 are distinctly better after dimensionless stress intensity factor of CCNBD is newly calibrated. The size effect of CCNBD specimens on fracture toughness is discussed based on the cohesive crack model. The geometric shape function is brought forward，which successfully resolve non-similarity problem of CCNBD when using the size effect law proposed by Bazant.

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TESTING STUDY ON MECHANICAL PROPERTY OF THENARDITE ROCK SALT

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2004, 23 (03): 391-391 doi:

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Testing study is made on the basic mechanical property of thenardite salt rock，which includes uniaxial compressive，indirect tensile and angle changed shear tests. Through the testing and analysis，it is found that thenardite salt rock is a kind of soft rock，the strength of which is low and the deformation is distinct. Moreover，the uniaxial compressive deformation and damage of thenardite are different from other rocks during four deformation phases. With variation of shearing angles，the strength curve equation of thenardite and calcium thenardite salt rocks are deduced.

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TESTING STUDY ON TRIAXIAL CREEP PROPERTIES OF
FROZEN SOIL TO DETERMINE THICKNESS OF FROZEN WALL

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2004, 23 (03): 395-395 doi:

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The specimens of frozen clay are used for carrying out the long-term creep tests under triaxial stress states so that the creep curves of the frozen clay are derived. According to the testing results， the nonlinear creep equation is proposed to describe the nonlinear creep property of frozen clay at different temperatures. By means of regression analysis， the values of creep parameters of frozen clay are obtained. The developing regularity of the viscoplastic region is approached with the aid of rhelogical theory of frozen soil and a formula is derived to calculate the thickness of frozen wall. At the same time the available methods are set forth to prevent fracture of the frozen pipes.

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REMOTE SENSING-ROCK MECHANICS——LAWS OF THERMAL INFRARED RADIATION AND ACOUSTIC EMISSION FROM FRICTION SLIDING INTERSECTED FAULTS AND ITS MEANINGS FOR TECTONIC EARTHQUAKE OMENS

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2004, 23 (03): 401-401 doi:

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The friction sliding of intersected faults is the third mechanism of tectonic earthquake. By use of biaxial loading system，thermal infrared (TIR) imaging system and acoustic emission (AE) devices， the TIR radiation and AE features of three kinds of intersected faults at different intersection angle were experimentally studied in the process of bi-sheared friction sliding. It is revealed that (1) the temporal sequential features of the AE and TIR radiation in the process of loading are controlled by fault behavior，and they show staged characteristics，(2) the features of AE and TIR radiation are tightly related to the geometrical structure of the intersected faults，and the abnormal TIR spots usually occur along the chief fault in condition that the principal stress is 45°in angle to the direction of the chief fault，and (3) the features of AE and TIR radiation from vertically intersected and slanting intersected faults are different，and the higher the intersection angle is，the stronger the TIR radiation is at the location of intersection point.

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TESTING STUDY ON INTERFACE SHEAR PROPERTIES
UNDER HIGH PRESSURE

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2004, 23 (03): 408-408 doi:

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The direct shearing test on characteristics of interfaces were conducted on the DSR-1 computerized high stress direct/post shearing system for standard sand，building sand，silt and clay interfaced with concrete，smooth metals and rough metals，respectively. The results show that the relationships between the normal stress and the peak shear strength，as well as between the normal stress and the residual shear strength are in accord well with Mohr-Column strength criterion under high stress，and the base influence is weak on the peak shear strength criterion of standard sand，but strong on the residual one. The residual shear strength criterion of concrete-base is related to the value of normal stress. When the normal stress is less than 2.44 MPa，shear failure takes place in standard sand，and when the normal stress is more than 2.44 MPa，the failure takes place on the interfaces. The shear failure of other base always happens in the interface. The curve of volumetric strain-shearing displacement in the shearing course of standard sand shows that when normal stress is less than 4 MPa，the curve appears as yield platform，and when it is more than 4 MPa，the curve presents hardening phenomenon according with the hyperbolic model and the corresponding volume change is contractive. The variance and direct-viewing analysis of the test data show that the normal stress is the main factor，soil property is the second one，roughness of base is the third one，and shearing rate is the fourth one to affect residual shear strength and initial shear stiffness.

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TESTING STUDY ON VARIATIONAL CHARACTERISTICS OF
ROCKMASS PERMEABILITY UNDER LOADING-UNLOADING
OF CONFINING PRESSURE

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2004, 23 (03): 415-415 doi:

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Based on permeability test，the varitional characteristics of rockmass permeability under loading- unloading of confining pressure are studied. The test results show that both the permeability of sandstone and that of granite with a single fracture declines with the increasing effective pressure，following the law of exponential decay. The permeability sensitivity of granite with a single fracture to effective stress is much stronger than that of sandstone，but the recovery capability of permeability of sandstone is more stronger than that of granite with a single fracture. Moreover，for sandstone and granite with a single fracture，there is obvious hysteresis effect for the restitution of permeability in the process of unloading of confining pressure.

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TESTING STUDY ON SHEAR STREANGTH OF UNSATURATED EXPANSIVE SOILS

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2004, 23 (03): 420-420 doi:

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Expansive soil is of potential for shrinking or swelling which can be caused by the change of water content. The shear strength of expansive soil is one of the key issues of soil mechanics and further studies are required for the need of analyses including evaluation of the stability of slopes，design of foundations and earth retaining structures. However，the strength behavior of expansive soil is rather complex especially compared to other types of soils. In this paper，the swelling pressure and strength of two typical expansive soils respectively collected from Heishan of Liaoning Province and Meishan of Nanjing are systemically investigated using the methods of conventional soil tests in order to understand its physical and mechanical properties and damage behavior. Meanwhile，the relationship between the swelling pressure and shear strength parameters such as effective cohesion and effective angle of internal friction and initial water content of unsaturated compacted expansive soil is established based on experimental test results. The swelling pressure and shear strength of expansive soils decrease sharply and the volume increases greatly with increasing water content. The ratio of the strength caused by matric suction to the swelling pressure is constant. Therefore a new formula of shear strength for unsaturated expansive soils is presented.

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TESTING STUDY ON INTERACTION CHARACTERISTICS BETWEEN FINE GRAINED TAILINGS AND GEOSYNTHETICS

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2004, 23 (03): 426-426 doi:

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Nonferrous copper ore tailing is used as reinforced filler soil in this paper. The interaction characteristics between fine-grained tailings and geosynthetics in different density，moisture content and vertical load are researched by pulling out test. At the same time， the reinforcement mechanism of fine-grained tailings is studied.

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UPLIFT TEST STUDY ON REINFORCED AEOLIAN SAND (II)
——ANALYSIS AND CALCULATION OF UPLIFT BEARING CAPACITY

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2004, 23 (03): 430-430 doi:

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Through soil analysis tests and model tests on aeolian sand of typical sand land，the uplift bearing capacity of aeolian sand of spread foundation was tested under 15 kinds of geogrid reinforced conditions. According to the test results，calculation model is defined，and theoretical calculation formula is put forward on uplift bearing capacity of geogrid reinforced sand land of spread foundation. The calculated and measured data are compared and they are closed to each other. The ultimate uplift bearing capacity is researched alone by the tests for sand land and geogrid reinforced materials，respectively. The difference between calculated and measured data is analysed. The effective reinforcement ways of building geogrid，that is，one and two layer geogrids，are proposed. Finally，the problems to be further studied are pointed out.

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APPLICATION OF DIGITAL CLOSE-RANGE PHOTOGRAMMETRY IN DEFORMATION MEASUREMENT OF MODEL TEST

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2004, 23 (03): 436-436 doi:

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The merits and demerits of many kinds of displacement measuring technique adopted mainly at present are discussed. The principles and methods of digital close-range photogrammetry are introduced. The error of this method is analysed and it is firstly applied to measure the displacement in sectional model test. This technique is of many advantages，such as contactless，simple apparatus，easy operation，low demand of environment，providing directly the elements of inner-azimuth，no error of negative pressure to plane，high automation and high precision. The test results indicate that the displacement field measured by this technique is of evident regularity and its measuring results fit well with the phenomenon occurring in the process of test. The difference between close-range photogrammetry and dial gauge is within 30 percent.

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2004, 23 (03): 441-441 doi:

[PDF] 363 KB (1153)

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According to the complex mining and geological conditions of deep excavation in Xinji mine，similarity model test is carried out for strata movement and surface subsidence due to coal extraction in No.3 mining district. Based on the analysis of repetitive mining with thick soil layers and deep coal seam，the special phenomena are put forward and the basic features of strata movement and the related parameters of mining subsidence are obtained. Also，the results are of tutorial impact for practical mining and governing of subsidence hazards.

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MODEL TESTING STUDY ON PREFABRICATED SPIRAL
V-NOTCH BLASTING

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2004, 23 (03): 446-446 doi:

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Prefabrication spiral V-notch blasting can control diameter of blasting block and reduce the second blasting by adjusting spiral angle. Model testing study is made on prefabricated spiral V-notch blasting，and hydromatic method is used to simulate the quasi-static process in blasting of explosive. It is found from the model test that the crack initiates and develops along the tip of spiral V-notch and that the bigger the spiral angle is the easier the crack initiates and the spiral V-notch hole model is easier to crack than the circle hole one.

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SCALE MODELING METHOD OF SHAKING TABLE TEST OF DYNAMIC INTERACTION OF PILE-SOIL-BRIDGE STRUCTURE IN GROUND OF SOIL LIQUEFACTION

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2004, 23 (03): 450-450 doi:

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Nowdays，scale modeling shaking table test is an important method to study aseismic ability and destroyable mechanism of engineering structure. The design of scale model is one of keys to insure that shaking table test can really reflect the dynamic characters of prototype. In order to solve the similitude problem of shaking table scale modle test of dynamic interaction of pile-soil-bridge structure in ground of soil liquefaction，based on the theorem of Bockingham p widely applied at present，the dimensional analysis method is used，and the constitutive strain-stress relationship of material between model and prototype and the dynamic response similarity of pile-soil interface are considered at the same time. Finally the method is put forward to solve artificial mass problem.

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MODEL TESTING RESEARCH ON CONTROLLING TUNNEL DEFORMATION IN LANDSLIDE FIELD WITH ANTISLIDE PILES

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2004, 23 (03): 457-457 doi:

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Taking Dongronghe tunnel landslide as an example，three model tests，i.e. test without antislide pile，tests with intervals of 16 m and 22 m between antislide piles and tunnel are made in laboratory. The variation regularities of pressure and deformation in sliding mass and the pressure behavior on tunnel lining are studied. The choice of the type of antislide piles，determination of the interval between antislide piles and tunnel，effect of antislide piles on stability of tunnel，and the distribution pattern of landslide-thrust are pointed out. The achievement of the research is important for controlling deformation of the tunnels in landslide field effectively.

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MODEL TESTING STUDY ON ROCK-SOCKETED
PILES IN SOFT ROCK

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2004, 23 (03): 461-461 doi:

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Model testing study is made on rock-socketed piles in soft rock. The test material consists of soft rock，epoxy mortar and red copper tubes. The test is carried out in triaxial apparatus. The whole load transfer behavior can reappear through strain measuring system.

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TESTING STUDY ON A NEW KIND OF FULLY-ANCHORED AND MULTI-WEDGED SLOTTED TUBE BOLT (BAMBOO-LIKE BOLT) RESEARCHED IN LABORATORY

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2004, 23 (03): 465-465 doi:

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A new kind of fully-anchored and multi-wedged slotted tube bolt，alias bamboo-like bolt，is different from currently bolt in functional mechanism and configuration. The bamboo-like bolt is of the characteristics of other full-anchored and end-anchored bolts，and especially the characteristics of multi-anchored bolts. The anchoring force of fully-anchored and multi-wedged slotted tube bolt is comprised of the friction between rock- mass and bolt，bolt end anchorage and multi-wedging force. Testing study is made in laboratory on the anchoring force of the bolt. According to the test result，the average drawing force the bolt is 918. kN and the drawing force of usual slotted tube bolt is only 66 kN，so that the drawing force of the bolt is increased 39%. At the same time，in order to know the working mechanism of the bamboo-like bolts，the RFPA (rock failure process analysis) is used to simulate the shear stress fields of bolt and displacement fields between bolt and rockmass. Moreover the bamboo-like bolts can be installed very simply in rockmass. The results show that fully-anchored and multi-wedged slotted tube bolt is of super mechanical capability and constructional convenience，and can be widely used in supporting and rock engineering.

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TESTING STUDY ON WORKING MECHANISM OF FULLY GROUTED BOLTS OF THREAD STEEL AND SMOOTH STEEL

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2004, 23 (03): 469-469 doi:

[PDF] 224 KB (2015)

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In order to study the bolting mechanism of full grouted bolt，a pull-out test of thread steel and smooth steel is carried out. The test results show that the depth of load distribution along thread steel is lower than that along smooth steel and the stress in thread steel attenuates quickly under tensile load. At the same time the test results show that the load distribution along the bolt of thread steel is the same with the result of elasticity theory under lower loads. The stress in superficial part concrete around thread steel is higher than that around smooth steel and the failure in superficial part of concrete around thread steel is more obvious. The thread steel bolt yields and the smooth steel bolt is pulled out under tensile loads of 280 and 300 kN，respectively. At last it is pointed out that there are compression，dilatancy and shear failure at the thread tendon and grouting interface and bond strength is enhanced significantly，which is the reason why the bond strength of thread steel bolt is higher. But there are only cohesion and friction at the smooth steel and grout interface，so that the bond strength is lower.

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TESTING STUDY AND ANALYSIS ON SOIL DISTURBANCE INDUCED BY PIPE JACKING CONSTRUCTION

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2004, 23 (03): 476-476 doi:

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In recent years，the technique of pipe jacking construction has been developed quickly and widely applied in water supply and drainage pipe projects in China，but it is required to study and discuss the mechanism of soil disturbance and changes of soil properties during pipe jacking. The mechanism of soil disturbance due to pipe jacking is investigated，and an improved method proposed to divide the sections of soil disturbance based on the results of former researchers. Analyses is made on the observational data of surface deformation，lateral deformation at sub-surface，pore water pressure，earth pressure，ground water level and in-situ pipe jacking construction records. The results show that the factors，such as ground conditions，construction techniques and the degree of site control，all affect soil disturbance，especially the degree of site control including jacking force，earth pressure，pipe line alignment，and slurry pressure. Change of earth pressure，pore water pressure，underground water level，surface deformation，and sub-surface movement all have direct relationship with distance between shield and testing section. Before the shield reaches the testing section (about 6～7 meters away)，the values of earth pressure，pore water pressure and underground water level go up to the peak. When the empennage of shield leaves the testing section，the values of surface uplift and sub-surface movement go up to the peak first and then descended. The results of in-situ testing prove the mechanism of soil disturbance well.

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MONITORING STUDY ON DRIFT DEFORMATION OF DAYE IRON MINE

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2004, 23 (03): 483-483 doi:

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In order to study drift deformation of Daye Iron Mine，4 convergence monitoring sections and 3 multi-point displacement monitoring sections are arranged. Through monitoring over one year，satisfactory data are obtained. Based on the measured data，it can be concluded that the whole drift is stable，the possibility of larger collapse is not large，and the deformation of drift floor is small. The main failure of rocks occurs on the mining side. There is obvious relationship between failure and mining，and the influence scope ranges about 100 meters. Convergence-control system can meet the needs of rock stability prediction of Daye Iron Mine during its producing period.

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INTERPRETATION OF DEFORMATION MONITORING OF UNDERGROUND ROADWAYS AND ITS APPLICATION
TO NO.2 DIGGINGS OF JINCHUAN MINE

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2004, 23 (03): 488-488 doi:

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The complexity of engineering condition at Jinchuan nickel mine is well known in China and abroad. The engineering geology condition of surrounding rock masses is very bad there. The activity of ground stress is highly intensitve. Especially the instability of tunnels located in the dynamic environment of mining is very serious. Based on the field investigations and deformation monitoring of underground tunnels at No.2 diggings of Jinchuan mine in long term，the main instability reasons of mining tunnels are synthetically analyzed. The main factors of influencing stability of tunnel are the activity of mining and the rock mass structure. It is pointed out that strong second support is better than limp one. Some measures to control stress are also given. The presented results will provide scientific instructions for the future mining.

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FEASIBILITY STUDY ON APPLICATION OF BOTDR TO HEALTH MONITORING FOR LARGE INFRASTRUCTURE ENGINEERING

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2004, 23 (03): 493-493 doi:

[PDF] 280 KB (2394)

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The characters of large infrastructure engineering and its requirements for the health monitoring are large scale，such as tens or hundreds of kilometers of tunnels and dikes，big diversity of engineering environment，such as oil pipes sometimes transiting the various geographic areas and time domain with quite complex engineering environment，high requirements of real-time and long-distance monitoring for some engineerings，such as dike monitoring during the flood，and high accuracy of monitoring，such as large-span gymnasium buildings and underground facilities requiring the order of micron or millimeter measureing accuracy. Hence the conventional measurement and monitoring methods and techniques are more and more not to meet the monitoring demands of health monitoring for large infrastructure engineering.
The Brilliouin optical time domain reflectometer (BOTDR) is a newly developed innovative measureing technique，which utilizes Brilliouin spectroscopy and optical time domain reflectometry to measure strain generated in optical fibers as distributed in the longitudinal direction. Because of the BOTDR’s distinctive characters，it has been paid more and more attention to and begun to be applied to monitoring system of various infrastructure engineerings，such as tunnels，river embankments and landslide prediction. In this paper，the operation principle and merits of BOTDR are introduced. Its application feasibility to the health monitoring for large infrastructure engineering are analysed based on authors’ research achievements and application cases. The relative topics about application of BOTDR are discussed in detail，which include installation methods of optic fiber，distance resolution impact for measuring results，temperature and humidity impact，fatigue effect of optic fiber，deformation conversion from strain and establishment of intelligent monitoring system. The research results show that the BOTDR is quite applicable to the health monitoring for large infrastructure engineering.

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DYNAMIC STRESS ANALYSIS OF SUBGRADE-BRIDGE TRANSITION SECTION OF QINSHEN RAILWAY

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2004, 23 (03): 500-500 doi:

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The damage of subgrade is made by the high speed train passing roadbed-bridge transition section. Qinshen special rail line for passenger is the first railway which has the capability to run over 160 km/h in our country. The dynamic stress of subgrade-bridge transition section under high-speed train action is analyzed and tested in Qinshen railway from DK46+765.95 to DK46+790.95. The longitudinal distributive regularities of dynamic stress of subgrade-bridge transition section，relationships between train speed and dynamic stress，and variety of dynamic stress with depth are analyzed. The analytical results indicate that the longitudinal distribution of dynamic stress has a tendency to increase with train speed，but when train speed exceeds 176 km/h，dynamic stress increases a little，even decreases slightly. Dynamic stress is attenuated very fast with depth of subgrade，and approaches static stress as depth increases.

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OBSERVATION AND ANALYSIS ON TIME-DEPENDENCY OF BUILDING SUBSIDENCE

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2004, 23 (03): 505-505 doi:

[PDF] 237 KB (948)

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According to the practical observation data of many engineerings，the basic regularity of time-dependency of building subsidence is found，and the estimation formula of the time-dependency is given，too.

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MULTIPARAMETERS TEST METHOD OF STATIC LOAD TESTING WITH BOTTOM AND TOP SETTLEMENTS OBSERVED

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2004, 23 (03): 510-510 doi:

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A multiparameters test method of static load is presented. Compared with routine test，the bottom and top settlements can be observed by this method and multiparameters are acquired. Based on these parameters，a general analysis can be made on the elasto-plastic compression of the pile，the side and bottom bearing capacity as well as the properties of the soil under pile.

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OPTIMUM DESIGN OF INTERACTION BETWEEN PILE AND PLATFORM
CONSIDERING VERTICAL STIFFNESS OF PILE

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2004, 23 (03): 514-514 doi:

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Based on the influence of difference of the diameter or length of bored pile on the vertical stiffness of pile，an analytical optimum design model of interaction between pile group and bearing platform is proposed with the vertical stiffness of pile into account. The bearing capacity of each pile could be fully utilized and the interacting characteristics of pile and platform is verified by means of engineering practice.

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CONSTRUCTION AND MONITORING OF GNAWING PILE
WITH CEMENT MIXING

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2004, 23 (03): 518-518 doi:

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The construction and test of gnawing pile with cement mixing are presented. This kind of pile was applied to road soil treatment engineering. There will be problem of unbalanced bearing capacity and bad quality of whole unity which would cause the problem of jumping vehicle running on the head crossroads，if only applying cement mixing pile to treat soil foundation. Instead，the application of gnawing pile with cement mixing can solve the problem.

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ON CRITICAL LENGTH OF PILE IN COMPOSITE FOUNDATION UNDER EMBANKMENT OF HIGHWAY

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2004, 23 (03): 522-522 doi:

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The definition and current study situation on critical length of pile in composite foundation are analyzed. By means of numerical analysis，the existence of critical length of pile in composite foundation under embankment of highway is revealed. Take the composite foundation at the section K102+990 of Ning¾Tong highway for example，the critical length of pile is studied by means of FEM and semi-analysis method.

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DISCUSSION ON “STUDY ON DYNAMIC STEADY STATE STRENGTH OF SOIL LIQUEFACTION”

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2004, 23 (03): 527-527 doi:

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ANSWER TO“DISCUSSION ON‘STUDY ON DYNAMIC STEADY STATE STRENGTH OF SOIL LIQUEFACTION’”

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2004, 23 (03): 528-528 doi:

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