174 results about "Shear strength (soil)" patented technology

The invention relates to a test method for simulating the shear resistant strength change of foundation pit precipitation soil. The test method comprises the following steps of: firstly, preparing an original-shape soil sample by using a fret saw, a soil cutter, a soil cutting disk, and the like; secondly, carrying out exhausting and water injection on the sample in a vacuum tank to be saturated;thirdly, mounting a test sample in which a latex film is sleeved in a three-axle pressure chamber; fourthly, solidifying the test sample at two phases through a three-axle ambient pressure system, wherein the test sample is restored to be in a natural self-weight stress state of a soil body by using the first-time solidification and the stress state of the soil body subjected to precipitation is simulated by using secondary solidification; fifthly, carrying out an un-drained shear test on the test sample through an axial loading system; and sixthly, after the test is ended, closing a motor and a valve and detaching the test sample. According to the test method disclosed by the invention, the influence of the reduction for water content of the foundation pit precipitation soil, the increase of effective stress and soil solidification and compaction on the soil shear resistant stretch is considered so as to provide reference for accurately selecting shear resistant strength indexes of the foundation pit precipitation soil and further provide guarantee for designing and constructing deep foundation pits of soft soil water-rich stratum safely, economically and reasonably.

The invention discloses a straight cut testing system for rock and earth mechanics, relating to a cutting system. The invention is composed of outer frame, horizontal loading system, vertical loading system, cut box, and measuring system; the horizontal loading system, the vertical loading system, the cut box and the cut box are fixed on the outer frame, respectively; the horizontal loading system, the vertical loading system and the measuring system are connected with the cut box, respectively. The invention has high measuring accuracy and good stability; all the data are automatically collected, thus reducing artificial reading error; it adopts variable frequency electric motor so as to reduce the manufacturing cost on the premise of assuring a stable cutting speed; all the parts are removable, convenient to transport and install. It can be used in determining peak values and remaining shearing strength of fine earth, coarse earth and soft rock and provide strength parameter for engineering design and rock and earth stability.

The invention relates to a method for treating landslide projects through combining a chemical electroosmosis method with micro anti-slide piles. The method comprises the following steps of: arranging metal electrodes and pouring different chemical solutions in boreholes and forming electroosmosis and chemical reaction under the action of a direct current field so as to enhance the shear strengthof potential failure surfaces of sliding zones; and then casting concrete in the boreholes and forming a micro reinforced concrete anti-slide pile system so as to provide a slide-resisting force. Themethod for treating the landslide projects through combining the chemical electroosmosis method with the micro anti-slide piles has the advantages and effects that: through carrying out electroosmosis reinforcement on the soft soil layers of potential landslide zones by using the chemical electroosmosis method, the coefficient of the shear strength of the potential landslide zones is remarkably increased, and the processing cost for the anti-slide piles or other treatment methods is effectively reduced; the bore diameter of the boreholes required by the micro anti-slide piles is small and themicro anti-slide piles are formed in identical boreholes to those for the chemical electroosmosis method through sequentially constructing, thus the difficulty and the cost for boring are low; and the shear strength and the slide-resisting force for landslide sliding zones are effectively enhanced. The method provided by the invention has the characteristics of simple construction technology, strong operability, convenience for quality control, obvious economic benefit and remarkable effect for treating landslides.

The invention discloses a multi-parameter micro-testing device for simulating a dry-wet cycle and a using method thereof, and relates to the technical fields of soil mechanics and geotechnical engineering, the multi-parameter micro-testing device includes a box body, a base, a soil sample box and a control panel, and the multi-parameter micro-testing device also includes a measuring system, a sampling system, a dry and wet circulation system and a displacement control system which are connected with the control panel; hot air generated by a hot air generating device and humid steam generated by an ultrasonic steam generating device are pressurized by a turbo pressurizing device and then enter from the soil sample box to a soil sample, at the same time, the change of water content in the whole process can be detected through optical fiber, and the control of the wet and dry cycle can be realized. The multi-parameter micro-testing device has the beneficial effects that a micro-static sounding probe can measure the penetration resistance of a soil conical tip, a cross shear plate can measure the undrained shear strength and shear modulus of the soil sample, the relationship between the micro-static sounding probe and the cross shear plate can be analyzed by testing of a specific soft soil sample. The multi-parameter micro-testing device can provide a most simple and feasible solution for calculation of the shear strength of on-site soil by static penetration testing.

The invention provides a prestressed pipe pile construction method based on the building information modeling (BIM). The construction method comprises the following steps that a, the layer thicknesses and the mechanical properties of various types of soil layers around pipe piles are input into the BIM according to a bore hole columnar section, and a 3 D model of the pipe piles is established; b, an internal force analysis diagram of each pipe pile under different excavation working conditions is educed through the BIM technology, the stress of each pipe pile under different excavation working conditions is analyzed, the maximum shear force value Vmax of each segment of the pipe piles under different excavation working conditions is figured out, and a shear force envelope diagram is drawn; and c, according to the stress analysis, H-shaped steel is arranged on a dangerous segment where the shear force value Vmax of the pipe piles is greater than V, and V is the shear strength of the pipe piles. According to the prestressed pipe pile construction method based on the BIM, the prestress analysis is conducted on the pipe piles through the BIM, and the reinforcement treatment is conducted on the pipe piles, so that the shear capacity of the pipe piles is increased.

The invention discloses a method for calculating the anti-capsizing critical built-in coefficient of an unsaturated soil foundation pit retaining wall and the application thereof. The method comprises the following steps that the plane strain shear strength unified solution with the nonlinear strength of unsaturated soil under high matrix suction is calculated; the active and passive soil pressure intensity of the unsaturated soil is calculated; the capsizing torque and the anti-capsizing torque of the anti-capsizing stability of the foundation pit retaining wall are calculated; when the matrix suction is not changed or in linear change along the depth, the cubic equation of an anti-capsizing critical built-in depth D1 is calculated, and therefore the anti-capsizing critical built-in coefficient of the unsaturated soil foundation pit retaining wall is obtained. According to the method, based on the plane strain shear strength unified solution of the unsaturated soil, the middle main stress effect and the nonlinearity of the strength of the unsaturated soil are considered, the anti-capsizing critical built-in depth equation of the foundation pit rigid retaining wall under two kinds of matrix suction distribution is derived, engineering application steps are given out, parameter influence characteristic analysis is conducted on anti-capsizing critical built-in coefficients which are newly provided, and a certain theoretical foundation is provided for reasonable design and construction of an unsaturated soil foundation pit supporting structure.

The invention discloses a soil body shearing testing device. The soil body shearing testing device comprises a special cutting ring, a pressurizing system and a mini-type injection instrument. The shearing testing device is characterized in that a plurality of side holes are formed in the periphery of the special cutting ring; the pressurizing system is composed of a pressurizing top cover, a lever and a weight; the mini-type injection instrument is provided with a conical probe, a reading window and the like. The invention discloses a soil body shearing testing method. According to the brand-new shearing testing device and shearing testing method for determining the shearing strength index of the soil body, the device is simple and convenient to operate; the shearing strength index of the soil body can be determined by only using one test sample and the uniformity of the test sample is guaranteed; the time for injecting the soil body by virtue of the mini-type injection instrument is short and the test sample can be controlled well to discharge water; all the characteristics are good for the accuracy of testing results; the soil body shearing testing device and the soil body shearing testing method are suitable for various civil engineering construction fields.

The invention provides a stability analysis method for hydromechanical coupling of an unsaturated soil slope, and belongs to the technical field of rock and soil. According to the stability analysis method, a Barcelona basic model more conforming to the property of the unsaturated soil is adopted for a constitutive model of the unsaturated soil, and the influence of suction force and the influenceof shear strength and compressive strength of a soil body are considered in the constitutive model. According to the strength reduction method for unsaturated soil slope stability analysis, the shearstrength of a soil body is reduced by reducing the cohesive force and the friction angle of the soil body. In addition, the reduction of the compressive strength of the soil body is taken into account by reducing the consolidation pressure in front of the soil body. The stability analysis of the unsaturated soil slope is carried out under the Cosserat continuum frame, and the influence of the microstructure effect of the soil body on the stability of the macroscopic slope is considered to a certain extent. According to the stability analysis method, various influence factors are considered, and the stability analysis accuracy of the unsaturated soil slope is improved.

The invention discloses a large-scale in-situ triaxial shear test device and a method thereof, and belongs to the technology of mechanical property test of soil in the field of geotechnical engineering. The device comprises a sample (10), a confining pressure system (20), a vertical pressure system (30), a counterforce system (40) and an automatic data acquisition system (50); the sample (10) is arranged in the confining pressure system (20); the vertical pressure system (30) and the counterforce system (40) are respectively arranged above and below the confining pressure system (20); and a vertical displacement meter of the automatic data acquisition system (50) is arranged in the sample (10). Compared with the prior art, an original structure of the sample can be maintained; confining pressure can be applied to the sample; an in-situ stress field of a measured soil body can be reproduced; the soil body can be damaged along the weakest surface thereof; and the size of the sample is large, so that the size effect influence is reduced. The large-scale in-situ triaxial shear test device and the method thereof have the characteristics of being real and comprehensive on the issue of researching the shear strength of the soil body; and test data are reliable, and powerful guarantee is provided for design and construction in the field of geotechnical engineering.

The invention discloses a method for testing swellability of carbonization process of magnesium oxide solidified soil and shear strength of carbonized soil, and belongs to the parameter test of solidified materials for civil engineering. The method comprises a test of temperature, resistivity and volume expansion of a magnesium oxide mixed soil sample during carbonization and solidification, and atest of shear strength of a carbonized sample, and specifically comprises the steps such as device assembly and connection, sample preparation, sensor debugging, carbonization maintenance and physical parameter test, direct shear test preparation and direct shear test. The method provided by the invention monitors the temperature and resistivity changes of the magnesia-solidified soil sample during carbonization and the volume expansion at different positions in real time to evaluate the carbonization progress and expansion characteristics of the material under different conditions. After thecarbonization curing, the carbonization sample is loaded to achieve its fully automatic direct shear test and resistivity test. The method avoids disturbance of the sample during the loading process,has simple operation steps and accurate parameter testing, and is of great significance for the engineering application and evaluation of carbonized solidified soil materials.

The invention discloses a liquefiable foundation device for micro-nano bubble processing and an operation method. In terms of a liquefiable sand layer in a foundation, a mixture of micro-nano bubbles and water is injected through a micro-nano gas-liquid mixture generator, a compressor, an air guide pipe, a hollow drilling pipe, a gas sprayer and the like, the micro-nano bubbles can stay in soil for a long time, the saturation is reduced, shearing strength of the soil is enhanced, and accordingly liquefaction resistance of the liquefiable sand layer is remarkably improved. When the liquefiable sand layer bears a vibration load, gas left in the soil can serve as a buffering agent and effectively buffer the tendency that pore water pressure rises, and accordingly the liquefaction resistance of the foundation is improved.

The invention provides a landslide dynamic stability evaluation method based on a strength reduction method. The method comprises the following steps: establishing a generalization model according tothe water level period scheduling condition of a reservoir area where a landslide is located, calculating a mechanical analysis time scale and a fluid analysis time scale by utilizing parameter data of a landslide rock-soil body, comparing the mechanical analysis time scale with the fluid analysis time scale, and determining a fluid-solid coupling simulation method; establishing a creep constitutive model of the slip band soil, and identifying creep parameters of the slip band soil; calculating the long-term shear strength of the slip band soil; constructing a landslide model, and calculatinga stress field, a strain field and a seepage field of the landslide; calculating landslide stability coefficients. The method provided by the invention reveals landslide deformation characteristics and an evolution mechanism under a hydrodynamic condition, achieves the dynamic evaluation of the stability of the creeping landslide in the reservoir area, and provides a basis for the prediction, early warning, prevention and control of landslides of the same type.

The invention discloses an in-situ measurement method for the shear strength of a soil body and an automatic remote real-time measurement system thereof. The in-situ measurement method comprises the steps of obtaining a shear wave velocity through a pair of shear wave velocity measurement piezoelectric patches according to a piezoelectric effect; measuring the moisture content of the soil body through a soil body moisture content sensor; obtaining the shear strength of the soil body according to a relation among the shear wave velocity, the moisture content of the soil body and the shear strength of the soil body. Exciting and receiving signals of the pair of the shear wave velocity measurement piezoelectric patches are connected with a micro controller through a phase discriminator and then are sent to an upper computer through a remote signal sending circuit and a remote signal receiving circuit; all devices are powered by a storage battery; the storage battery is connected with a solar power supply device. The shear strength of the soil body is measured according to the shear wave velocity of the soil body and the moisture content of the soil body; in-situ, remote, real-time and automatic measurement is executed; an on-site, real-time and remote monitoring means is supplied to observation of possible catastrophe processes of landslide and debris flow hidden points, research on the rule of the landslide and debris flow disasters and final forecast of the landslide and debris flow disasters.

During triaxial compression test, a soil specimen experiences reduction of its height with increase in its diameter. New cross-sectional area is calculated assuming uniform increase in diameter. This condition is seldom met in actual soil specimens, because specimen undergoes non-uniform increase in diameter and very often with localized bulging in specimen affecting the accuracy of calculation of deviator stress, shears strength and volume change characteristics. The expandable jacket included in this invention consists of circular segmental metal plates wrapped around the soil specimen and elastomeric rubber bands or rings around the segmental plates to permit uniform radial expansion and maintain uniform diameter of the specimen during the test and thereby providing accurate values of deviator stress, volume change characteristics and shear strength of soil specimen. The calibration device for calibration of expandable jacket shall provide the magnitude of correction to be made in deviator stress.

The invention relates to the technical field of soft soil layer foundation pits, and discloses a soft soil layer slope along a foundation pit. The soft soil layer slope comprises a plurality of steel plate piles vertically arranged in the soft soil layer slope, the multiple steel plate piles are erected side by side to form a steel plate wall, the steel plate wall is arranged in the length direction of a slope face platform, the upper end of the steel plate wall extends on the slope face platform, the lower end of the steel plate wall extends to the position below a potential sliding face, and the steel plate wall is used for foundation pit supporting; in this way, the shear strength of the foundation pit soft soil layer slope is improved, the anti-sliding stability of the foundation pit soft soil layer slope is increased, and meanwhile, the construction is convenient and rapid; and after a foundation pit supporting project is completed, when backfilling is started, the steel sheet piles can be lifted and recovered to be reused, the engineering investment is greatly saved, and going green and environmental protection are achieved.

A portable soil body in-situ shear test device includes four parts: an active force system forming arranged externally, a passive shear system and an electromagnetic loading system forming arranged internally, and a ring knife system arranged at a bottom. Compared with the conventional in-situ soil shear strength test device and test method, the present invention is convenient to install and carry as well as simple to operate, and has strong applicability. The present invention is suitable not only for layered soils with large cross-plate shear test errors, but also for soils with different consolidation degrees at various sites and various terrains. A test method adopting the device can simulate the shear strength of the soil mass under different overburden loads without disturbing the mechanical properties of the in-situ soil mass, which has high promotion value in the test of in-situ soil shear strength.

The invention belongs to the technical field of geotechnical engineering, and discloses a comprehensive prevention and control system applied to a gravel soil side slope. According to the comprehensive prevention and control system, the good slope anti-seepage effect is achieved by burying drainage blind pipes and rapid drainage pipes in a slope surface layer soil body, arranging an intercepting ditch at the top of the slope, arranging a drainage channel at the foot of the slope and performing planting and greening on the slope surface, and the influence of surface water infiltration such as rainfall on the slope stability is reduced; after spring type spiral steel bars are put into pile holes, concrete doped with an expanding agent is poured into the pile holes to form miniature anti-slide piles, prestressed anchor cables are arranged to improve the shear strength of the side slope, and the stability among a potential sliding surface upper landslide mass, a potential sliding belt anda lower stable soil mass is enhanced; a plain concrete retaining wall is arranged at the foot of the slope to support the side slope, and a deep drainage pipe is drilled in the concentrated seepage area to effectively cut off the concentrated seepage, and water is collected and guided out of the slope; and finally, the anti-seepage drainage and reinforcement effects on the side slope are remarkable, and compared with traditional electro-osmosis drainage, energy consumption is reduced, economic benefits are remarkable, and operability is high.

The invention belongs to the technical fields of civil engineering and geotechnical testing, and provides a novel compaction grouting soil nail and a pull-out test device thereof. The novel compactiongrouting soil nail is expanded by injecting cement slurry into special latex balls into to achieve compaction anchoring with a surrounding soil body. The pull-out test device comprises the novel compaction grouting soil nail, a test box, a grouting pressurization system, a pulling system, a measurement system and a data acquisition system and can be used for pulling tests of the novel compactiongrouting soil nail. The novel compaction grouting soil nail and the pull-out test device thereof have the beneficial effects that the novel compaction grouting soil nail can effectively avoid bleeding, penetration grouting or split grouting in the surrounding soil body; and the pull-out test device can be used for simulating compaction grouting processes under different saturation conditions and exploring the shear strength of a soil-nail interface and the response of the surrounding soil body to provide a basis for the design and safety assessment of the novel compaction grouting soil nail.

The invention discloses a drawing type soil layer shearing strength testing device and a method for testing by using the same. The drawing type soil layer shearing strength testing device comprises a base, a drawing type soil layer shearing strength tester, a drawing rod and a displacement sensor and is characterized in that the base and the drawing type soil layer shearing strength tester are arranged on a test point of a soil layer, a connecting rod joint of the drawing type soil layer shearing strength tester is connected with the drawing rod placed in the soil layer, a hand wheel of the drawing type soil layer shearing strength tester is rotated to lift the drawing rod until the soil layer is sheared, and the shearing strength of the soil layer is tested. The drawing type soil layer shearing strength testing device and the method for testing by using the same are suitable for in-site test of total dewatering-free shearing strength of soil layers such as a foundation pit, a side slope and the like and rapidly making engineering evaluation on the soil layers.

The invention discloses a slope soil shear strength site test device and method. The device comprises a cuboid framework, wherein a cuboid soil mass frame is arranged in the framework body of the cuboid framework, the cuboid soil mass frame is of a cuboid frame structure formed by a steel sheet A, a steel sheet B and two side steel sheets, the steel sheet A is parallel to the steel sheet B, and the two side steel sheets are parallel to each other; jacks are installed between the inner wall of the cuboid framework and the outer wall of the steel sheet A closely and correspondingly, and located on the upper portion of the cuboid framework and the upper portion of the cuboid soil mass frame; a fixed rod is arranged on the inner wall of the cuboid framework, a forcemeter is installed on the fixed rod and provided with a dowel bar, and the end of the dowel bar of the forcemeter is fixedly connected with the outer wall of the steel sheet B; a dividing ruler is arranged on the upper portion of the cuboid framework. By the adoption of the device, slope soil shear strength site real-time testing of different types of slope soil can be achieved. Furthermore, the device has the advantages of being simple in structure and low in machining cost.

The invention discloses a test system and method for directly measuring interface shear strength at different temperatures, and belongs to the technical field of research on rock soil, geology, environment and the like. Aiming at the problems of insufficient precision, poor anti-interference capability, limited measurement parameters and the like of the existing direct shear test technology, the invention provides a test system and method for directly measuring the interface shear strength at different temperatures. The device provided by the invention mainly comprises a lower shearing box-measuring device, a constant-temperature water bath tank, a heating and refrigerating circulator and a loading device, and a tension and compression stress sensor and a pore water pressure sensor are used as internal high-precision measuring components of a structure; a method for testing and calculating the properties of the structure-soil interface at different temperatures and roughness is provided, and the interface strength and pore water pressure of the structure-soil interface can be measured by using the method. The relationship between the cohesive force and the friction angle of the structure-soil interface and the temperature, the roughness and the shearing rate can be obtained through calculation and analysis.

The invention discloses a device and a method for rapidly measuring suction and shear strength of an unsaturated soil matrix. The device comprises a centrifugal machine cabin, a thread cutting workbench, a pressurizing system, a pressure sensor, a breathable pressure applying cover, a shearing box, a drainage collecting box, a ball, a sliding way, a shearing force applying system, a shearing forcesensor and a displacement sensor, wherein the shearing box is connected with the drainage collecting box and makes contact with a sliding way of the thread cutting workbench through the ball, the pressurizing system is installed at the axis of the cabin, and pressure acts on the sample through a breathable pressure cover, the shearing force applying system is mounted at the bottom of the centrifugal machine cabin, shearing force vertically acts on the lower shearing box upwards, and force and displacement values are collected through the pressure sensor, the shearing force sensor and the displacement sensor. The method comprises the following steps of preparing a sample, installing a sample, matrix suction measurement, unsaturated strength measurement and moisture content measurement. Thedevice is advantaged in that rapid measurement of unsaturated sample matrix suction and unsaturated strength can be realized, and the device is of great significance to research of unsaturated soil.

The invention relates to the technical field of foundation trench backfilling, and discloses a foundation trench backfilling construction method based on premixed fluid solidified soil. The method comprises the following steps that before a foundation trench is backfilled, the foundation trench is cleared to the elevation of the bottom surface of a foundation, and sundries such as falling loose garbage, mortar and stones are cleaned away; the quality of the fluid solidified soil used for backfilling is checked; the fluid solidified soil is used for backfilling; after soil filling is completedcompletely, datum line placement and leveling are conducted, wherein leveling is conducted on places higher than the standard elevation in time according to a datum line, and soil filling and tampingare conducted on places lower than the standard elevation; the mass density of the dry soil is measured; and after the mass density meets the specified requirement, and layered soil is laid on the upper portion of the fluid solidified soil. In the process of backfilling the foundation trench, the fluid solidified soil for backfilling has the advantages of high compactness, high shear strength andhigh compressive strength. After the fluid solidified soil is solidified, the fluid solidified soil is not dissolved after being soaked in water at normal temperature, and has high stability in waterand high durability. The strength of the foundation trench is improved, thereby ensuring the construction effect.

The invention discloses soil shear strength testing equipment and a testing method, and relates to the technical field of soil shear strength testing equipment. The technical problem that a common direct shear apparatus is inaccurate in measurement of shear force borne by soil is solved. According to the technical scheme, the device is characterized by comprising a bottom plate and a shearing boxlocated on the bottom plate; the shearing box comprises a lower box body and an upper box body arranged on the lower box body in a sliding mode. A driving device and a force measuring device are respectively arranged at two ends of the upper surface of the bottom plate in the length direction of the shearing box; the force measuring device comprises a supporting plate, an abutting block and a force measuring ring, an extending strip is vertically arranged on the outer side wall of the upper box and faces the side wall of the force measuring ring, a connecting block is arranged at the end, awayfrom the upper box, of the extending strip, and an abutting groove is formed in the side wall, away from the extending strip, of the connecting block; scale marks are arranged on the upper surface ofthe supporting plate in the length direction of the supporting plate, a stopwatch is arranged on the upper surface of the supporting plate, and the effect of effectively improving the accuracy of thesoil direct shear apparatus for measuring the soil shear strength is achieved.

The invention relates to the field of slope engineering stability evaluation, in particular to a slope shear strength parameter inversion analysis method based on equivalent soil pressure action, the method comprises the following steps: acquiring rock mass material parameters, rock mass test data and monitoring data; establishing a numerical calculation model according to slope field data; performing rock mass shear strength parameter inversion analysis in a soil initial stress field by using the numerical calculation model; comparing the slope stress field with the initial ground stress field under the action of the equivalent soil pressure, and carrying out inversion analysis on the shear strength parameters c and phi of the rock mass again; correcting the initial parameters through the inversion parameters, and obtaining the shear strength parameter cohesive force c and the internal friction angle phi of the rock mass. According to the method, in parameter inversion analysis of the side slope with the covering layer, the slope pressing effect of the covering layer is considered, the problem that the rock mass inversion parameters cannot be obtained due to the fact that the sliding surface is always in the covering layer due to the fact that the parameters of the covering layer are relatively low is solved, and then the shear strength parameters of the rock mass can be obtained more accurately and reasonably.

The invention discloses an in-situ detection shearing device of a loess hole. The in-situ detection shearing device comprises a motion carrier, a shearing part and an air bag carrier, wherein the motor carrier drives the shearing part and the air bag carrier to climb a wall and walk, the loess shearing tool is borne by the shearing part, the shearing part is used for driving the shearing tool to rotate and cut after the motor carrier reaches a detection position, the air bag carrier is connected with the shearing part and comprises a main air bag carrier and a side air bag carrier, the main air bag carrier bears a main air bag and is used for solidifying hole soil, the side air bag carrier bears a side air bag, and the motion carrier and the side air bag are jointly used for measuring a shearing force. In the shearing force, in-situ measurement test of soil shear strength can be performed in a loess underground pipeline, and soil shear strength at different soil layer positions can beaccurately measured.

The invention provides a rock-soil shear strength parameter fine acquisition method under excavation supporting conditions. The method comprises the following specific steps: step 1, judging a potential slip crack surface of a soil body according to the actual condition of unloading the rock-soil body; step 2, judging the states of different regions of the rock-soil body according to the potentialslip crack surface, and dividing the rock-soil body into a region I, a region II and a region III; step 3, selecting different shear strength parameter test methods according to the stress paths of the stress states of the region I, the region II and the region III in the rock-soil body excavation process; and step 5, obtaining unloading shear strength parameters of the rock-soil bodies in different regions according to different test methods selected by rock-soil bodies in different regions, and determining the soil body stability of the soil bodies in different regionss. According to the method, region division is carried out according to the stress state change under the rock-soil body unloading condition, an appropriate triaxial test method is selected for different regions, then rock-soil body unloading shear strength parameters can be obtained in a refined mode and a more detailed and accurate basis is provided for foundation pit or slope safety and stability analysis.

The invention discloses a progressive wet-dry cycle testing device comprising a water supply container, a soil column system and a gas permeable system. The soil column system is connected with the water supply container, and the gas permeability system is connected with the soil column system. The water supply container includes a water container and a circulating water container which are concentrically arranged, the soil column system includes a base, a bottom layer and a plurality of standard layers which are connected together, and the gas permeability system includes a plurality of gas permeability pipes with gas permeability through-holes, and the plurality of gas permeability pipes are in inserted connection. The invention also discloses a use method of the test device. Through theprogressive dry-wet cycle test device and the use method, the wet and dry cycle method is in conformity with the actual working conditions in engineering practice, the accuracy of test results is improved, soil samples under multiple times of wet and dry cycles and shear strength parameters thereof can be obtained by one soil column test model, and the gas permeability through-holes are arrangedon the walls of the gas permeability pipes and the walls of the standard layers, so that the cycle of the wet-dry cycle is shortened.