Experimental system for determining the range of the dilatancy zone of dense fine-grained soils and method of use thereof

Abstract

The present application relates to the field of testing or analyzing materials by means of determining the chemical or physical properties of materials, in particular to an experimental system for determining the range of the shear dilation zone of dense fine-grained soil and a method for using the same. The experimental system for determining the range of the shear dilation zone of dense fine-grained soil comprises a preparation subsystem (1), a cutting subsystem (2), a measurement subsystem (3) and a control subsystem (4), characterized in that: the preparation subsystem (1) comprises a suction device (11), a gas-water separation device (12) and a preparation pool (13) and the like; the cutting subsystem (2) comprises a cutter tooth (21), a tooth seat (22) and a force sensor (23) and the like; the measurement subsystem (3) comprises a water-permeable stone (31) and a water pressure sensor (33) and the like; and the control subsystem (4) comprises a data acquisition instrument (41), a data line (42) and a control device (43). The present application is close to the actual situation and has good controllability.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of experimental systems for determining the scope of dense fine-grained soil shear dilation zone and its use method. BACKGROUND

[0002] As the main ship in dredging industry, the trailing suction dredger plays an important role in all kinds of channel dredging, port construction and reclamation project. However, the seabed of main port and approach channel located in the long coastline is complex and changeable. The soil of dense and cemented silt and silty sand is often encountered, which has the characteristics of high density, low compressibility, high strength and large bearing capacity. It is as hard as "iron plate", so it is called "iron plate sand". The mean grain size is between 0.02 and 0.5 mm, the average natural density is between 1.8 and 1.95 g / m 3 , the relative density is more than 2 / 3, and the strength parameter has an average cohesion of 5-15 kPa in addition to the internal friction angle of more than 30°. The soil is between sand and clay in composition, so it has the characteristics of high strength and large bearing capacity, and the standard penetration blow count is generally more than 30 N.

[0003] Due to the above characteristics of the soil, the efficiency of the trailing suction dredger in dredging the soil is very low, and the progress is slow. For example, the "iron plate sand" in Huanghua Port of Hebei Province and the Yangtze River Estuary, the dredging concentration of the trailing suction dredger is generally very low, often less than 1.10 t / m 3 .

[0004] In view of the above situation, the relevant construction units and design departments propose the idea of high-pressure water flushing, that is, to open a hole in the middle of the rake teeth, and then to use water flow of 4-6 bar to assist in breaking the soil, but the effect is very limited.

[0005] Through research, it is found that the "iron plate sand" is difficult to dig because the soil has obvious shear dilation. During the cutting of the rake teeth, a certain range of shear dilation zone is formed on the rake teeth surface. The pore water pressure in the shear dilation zone is negative, which increases the effective stress of the soil, significantly improves the shear strength of the soil, and further increases the cutting resistance of the rake teeth. The main reason why the high-pressure water flushing has little effect on the "iron plate sand" is that the existence of the shear dilation zone is not recognized. Although the water flushing hole is set, the water is not injected into the shear dilation zone or the area with the strongest shear dilation, so the shear strength of the soil cannot be reduced, and the resistance reduction effect is very limited. SUMMARY

[0006] In order to overcome the defects of the prior art, provide a soil shear dilation zone test equipment close to the actual situation and good control, the present application discloses a kind of experimental systems for determining the scope of dense fine-grained soil shear dilation zone and its use method.

[0007] The present application achieves the purpose of the invention through the following technical solutions:

[0008] An experimental system for determining the range of the shear dilation zone of dense fine-grained soil, comprising a preparation subsystem, a cutting subsystem, a measurement subsystem and a control subsystem, the preparation subsystem is arranged on the ground, the cutting subsystem is arranged on the preparation subsystem, the measurement subsystem is arranged on the cutting subsystem, and the control subsystem is connected with the measurement subsystem, characterized in that:

[0009] The preparation subsystem comprises a suction device, an air-water separation device, a preparation pool, a supply device, a vibrating compaction device and a leveling device, and is used to prepare various types of dense fine-grained soil including dense fine sand, dense silty sand and dense silt, etc.

[0010] The preparation pool is arranged on the ground, and a soil body is arranged in the preparation pool; the suction device and the air-water separation device are arranged on one side of the preparation pool; the supply device is arranged on the other side of the preparation pool; the vibrating compaction device and the leveling device are arranged above the soil body in the preparation pool; the suction device sucks the air in the soil body in the preparation pool through the air-water separation device; the air-water separation device separates the water contained in the air sucked by the suction device; the supply device outputs air-free water to the preparation pool; the vibrating compaction device vibrates and compacts the soil body in the preparation pool; and the leveling device smoothes the surface layer of the soil body in the preparation pool.

[0011] The cutting subsystem comprises a cutter tooth, a tooth holder, a force sensor, a cutting connecting device, an angle adjusting hydraulic cylinder, a height adjusting hydraulic cylinder, a trolley, a track and a traction system, and is used to dynamically cut the soil body.

[0012] The traction system is arranged on both sides of the top of the preparation pool; the track is fixed above the preparation pool; the trolley is movably arranged on the track through the wheels at the bottom; the traction system ties the two ends of the trolley; the top end of the cutting connecting device and the height adjusting hydraulic cylinder are fixed in sequence at the bottom of the trolley; the moving end of the piston rod of the height adjusting hydraulic cylinder is connected to the middle part of the cutting connecting device; the cylinder body of the angle adjusting hydraulic cylinder is fixed at the front part of the cutting connecting device; the moving end of the piston rod of the angle adjusting hydraulic cylinder is connected to the front part of the cutting connecting device; the tooth holder is fixed at the top end of the cutting connecting device; the cutter tooth and the force sensor are both fixed on the tooth holder; and the trolley moves along the track under the traction of the traction system, thereby driving the cutter tooth to linearly cut the soil body.

[0013] The measurement subsystem comprises a water-permeable stone, a water pressure sensor, silica gel and a communication cable, and is used to measure the pore water pressure at each position of the interface between the cutter tooth and the soil body in real time during the cutting process of the soil body.

[0014] The water pressure sensor is arranged in the hole drilled by the toothed cutter and fixed by silica gel, one end of the water pressure sensor is provided with a communication cable which is drawn out from the hole, the other end of the water pressure sensor is provided with a water-permeable stone, the upper surface of the water-permeable stone is flush with the toothed cutter, and the lower surface of the water-permeable stone is in contact with the water in the soil under pressure;

[0015] The control subsystem comprises a data acquisition instrument, a data line and a control device, and is used to automatically acquire and store the pore water pressure data generated in the process of cutting the soil by the toothed cutter,

[0016] The communication cable at one end of the water pressure sensor is connected to the data acquisition instrument, the force sensor is also connected to the data acquisition instrument through the communication cable, the data acquisition instrument is connected to the control device through the data line, the control device is also connected to the cutting subsystem through the data line, the control device is provided with a parameter setting module, a cutting control module, an acquisition control module and a data processing module, and while automatically storing the pore water pressure data, the data can be transmitted to other electronic devices through the network.

[0017] The experimental system for determining the range of the shear dilation zone of dense fine-grained soil is characterized in that:

[0018] In the preparation subsystem:

[0019] The suction device comprises a vacuum pump, a suction gas pipe and a suction valve, the suction gas pipe is connected to the gas-water separation device at the air inlet end of the vacuum pump, and the suction valve is connected in series to the suction gas pipe;

[0020] The gas-water separation device comprises a separation valve, a gas-water separation tank, a separation gas pipe and a vacuum gauge, the gas-water separation tank is connected to the suction gas pipe at the gas outlet end, the gas-water separation tank is connected to the preparation tank through the separation gas pipe at the gas inlet end, the water body is collected in the gas-water separation tank, the air in the soil in the preparation tank is sucked by the vacuum pump, and then input into the gas-water separation tank through the separation gas pipe, the water in the air is collected in the lower part of the gas-water separation tank to form the water body, the air separated from the water is discharged by the vacuum pump through the suction gas pipe, the separation valve is arranged at the upper part and the bottom part of the side of the gas-water separation tank, the separation valve is also connected in series to the separation gas pipe, and the vacuum gauge is arranged at the top of the gas-water separation tank, the gas-water separation device is used for separating the gas-water mixture sucked by the vacuum pump, so as to avoid damaging the vacuum pump;

[0021] The preparation pool comprises a side wall, a foundation, gravel, non-woven fabric, a filter screen, a sealing film, a joint, a membrane outlet device and a drainage plate, the foundation is built on the ground, the side wall is built around the foundation, the foundation and the side wall are of a turning building structure or a concrete structure, the inner and outer surfaces of the foundation and the side wall are coated with a waterproof layer, the top surface of the foundation and the lower part of the inner surface of the side wall are paved with gravel as a drainage and exhaust passage, the top surface of the gravel is paved with non-woven fabric and the filter screen as a filter layer from bottom to top, the soil used for the experiment is stacked on the filter screen, the top surface of the soil is paved with the filter screen, the non-woven fabric, the drainage plate and the sealing film from bottom to top, so that a closed space is formed around the soil, the drainage plate is connected to the membrane outlet device through the joint, the membrane outlet device is connected to the separated gas conveying pipe, and the length of the inner cavity of the preparation pool is not less than 40 m;

[0022] The supply device comprises a water conveying pipe, a supply valve and a water tank containing still water, the water tank is connected to the preparation pool through the water conveying pipe at the bottom to input the still water into the preparation pool, and the supply valve is connected in series on the water conveying pipe to control the start and stop of the water conveying and the water volume.

[0023] The vibration and compaction device is used for further tamping the soil after the soil is extruded by the vacuum pump, so that the voids in the soil are reduced to increase the compaction degree of the soil.

[0024] The leveling device is fixed on the truss of the trolley, and the trolley drives the leveling device to level the surface of the soil when the trolley moves.

[0025] The experimental system for determining the range of the shear dilation zone of the compacted fine-grained soil is characterized in that:

[0026] In the cutting subsystem:

[0027] The cutter is fixed on the cutter holder, and the force sensor is fixed on the cutter holder through the flange joint, and the force sensor synchronously measures the cutting resistance when the cutter cuts the soil.

[0028] The cutting connecting device comprises a cutting connecting device, a cutting connecting plate, a cutting connecting frame and a cutting connecting arm, one end of the cutting connecting plate is connected to the force sensor through a bolt-nut assembly, the other end of the cutting connecting plate is connected to one end of the cutting connecting frame through a bolt-nut assembly, the other end of the cutting connecting frame is rotatably arranged on one end of the cutting connecting arm through hinging, and the other end of the cutting connecting arm is rotatably arranged on the trolley through hinging.

[0029] The cylinder body of the angle adjusting hydraulic cylinder is fixed on the cutting connecting arm, the moving end of the piston rod of the angle adjusting hydraulic cylinder is rotatably connected to the cutting connecting frame through hinging, and the cutting connecting frame is driven to rotate by the extension and retraction of the piston rod of the angle adjusting hydraulic cylinder, so that the cutting angle of the cutter is adjusted.

[0030] The cylinder body of the height adjusting hydraulic cylinder is fixed at the bottom of the trolley, and the moving end of the piston rod of the height adjusting hydraulic cylinder is rotatably connected to the cutting connecting arm through a hinge, and the height of the cutter tooth is adjusted by driving the cutter tooth to move up and down through the extension and contraction of the piston rod of the height adjusting hydraulic cylinder, so that the thickness of the soil cut by the cutter tooth is adjusted.

[0031] The traction system comprises a steel wire rope, a power system, a traction controller and a rack, the rack is fixed on one side of the preparation pool, the power system and the traction controller are arranged on the rack, the traction controller is connected to the power system, the angle adjusting hydraulic cylinder and the height adjusting hydraulic cylinder through signal lines respectively, and the traction controller is also connected to the control device through a signal line.

[0032] The experimental system for determining the range of the shear dilation zone of dense fine-grained soil is characterized in that:

[0033] The power system is selected from a winch or an electric hoist, and the traction controller is selected from a programmable controller, a single-chip microcomputer or a microcomputer;

[0034] The water pressure sensor is selected from a miniature pressure sensor;

[0035] The control device is selected from a microcomputer;

[0036] The control device controls the power system, the angle adjusting hydraulic cylinder and the height adjusting hydraulic cylinder through the traction controller according to the set parameters, so that the cutter tooth moves back and forth according to the set parameters to cut the soil, the data acquisition instrument collects the cutting resistance value measured by the force sensor and the pore water pressure value measured by the water pressure sensor in real time according to the set parameters and transmits them to the controller, the controller stores the received cutting resistance value and pore water pressure value, and the controller can also transmit the cutting resistance value and pore water pressure value to other electronic devices through a network, after the cutting reaches the set requirement, the control device controls the power system, the angle adjusting hydraulic cylinder and the height adjusting hydraulic cylinder to stop running and return to the initial position through the traction controller, and the control device then processes the received cutting resistance value and pore water pressure value.

[0037] The use method of the experimental system for determining the range of the shear dilation zone of dense fine-grained soil is characterized in that the following steps are implemented:

[0038] S1. Soil preparation: the soil is put into the preparation pool, and the air in the soil in the preparation pool is sucked by a vacuum pump, first input into a gas-water separation tank through a separation gas supply pipe, and the water in the air is collected in the lower part of the gas-water separation tank to form a water body, the air separated from the water is discharged by the vacuum pump through a suction gas supply pipe, and the water tank is connected to the preparation pool through a water supply pipe at the bottom to input gas-free water into the preparation pool.

[0039] S2. Setting: In the maintenance mode, the control device controls the power system through the traction controller to implement zero position correction on the trolley and the steel wire rope respectively, the control device sets the cutting speed of the cutter tooth, the acquisition frequency of the force sensor and the acquisition frequency of the water pressure sensor through the parameter setting module, and powers on the frequency converter of the power system to make the frequency converter in a ready state, while ensuring that the brake and tensioning hydraulic pressure of the traction system are normal;

[0040] S3. Cutting: the cutting control module of the control device controls the power system, the angle adjusting hydraulic cylinder and the height adjusting hydraulic cylinder through the traction controller respectively, adjusts the cutting angle of the cutter tooth by driving the cutting connecting frame to rotate through the extension and retraction of the piston rod of the angle adjusting hydraulic cylinder, adjusts the height of the cutter tooth by driving the cutter tooth to move up and down through the extension and retraction of the piston rod of the height adjusting hydraulic cylinder, thereby adjusts the thickness of the cutter tooth cutting the soil, and the trolley moves along the track under the traction of the traction system, thereby driving the cutter tooth to linearly cut the soil at the set cutting speed;

[0041] S4. Measurement: the force sensor synchronously measures the cutting resistance at the set acquisition frequency, and the water pressure sensor synchronously measures the pore water pressure at the interface between the cutter tooth and the soil during the cutting of the soil at the set acquisition frequency;

[0042] S5. Acquisition: the acquisition control module of the control device receives and stores the cutting resistance value measured by the force sensor and the pore water pressure value measured by the water pressure sensor through the data acquisition instrument;

[0043] S6. Analysis: the data processing module of the control device determines the shear dilation zone range according to the received cutting resistance value and pore water pressure value, and the specific steps are as follows:

[0044] Firstly, mark the positions where the measured pore water pressure is positive with “+” and the positions where the measured pore water pressure is negative with “-”; secondly, for the adjacent regions with positive and negative values, perform difference processing to obtain the positions where the pore water pressure is 0; thirdly, plot the positions where the pore water pressure is 0 as data points on the tooth surface plane diagram of the cutter tooth; and finally, connect the points where the pore water pressure is 0 into a line, which is the demarcation line between the shear dilation zone and the non-shear dilation zone, and the region with negative pore water pressure value is the finally determined shear dilation zone range;

[0045] S7. Reset: stop the trolley to stop the cutting of the cutter tooth on the soil, and then make the trolley retreat to the initial zero position at the set speed.

[0046] The use method of the experimental system for determining the shear dilation zone range of dense fine-grained soil is characterized in that:

[0047] In step S1, the soil put into the preparation pool is dug from the construction site, and impurities (such as stones, garbage, branches, etc.) are removed to ensure the uniformity of the soil, and the indicators of the soil put into the preparation pool are kept consistent with the soil at the construction site;

[0048] In step S3, the moving speed of the cutter tooth when cutting the soil is not greater than 3 m / s, and the fluctuation amplitude of the moving speed is not greater than 5%. When cutting, the first 5 m is an acceleration section in which the speed increases from zero to the moving speed, and the last 5 m is a deceleration section in which the speed decreases from the moving speed to zero. The cutting section between the acceleration section and the deceleration section has a length not less than 30 m.

[0049] In step S5, the acquisition control module of the control device acquires the cutting resistance value measured by the force sensor and the pore water pressure value measured by the pore water pressure sensor at a frequency of once per 1 mm of operation of the cutter tooth.

[0050] In order to eliminate the shear dilatancy effect of the soil, thereby reducing the shear strength of the soil and further reducing the cutting resistance of the rake tooth, it is necessary to develop a related experimental system to truly reproduce the actual process of the rake tooth cutting the soil at the construction site, carry out a series of model experiments through the experimental system, determine the distribution of the negative pore water pressure along the tooth surface during the cutting process of the soil, and determine the distribution range of the shear dilatation zone along the rake tooth surface from the experimental results.

[0051] In the cutting process of the dense fine-grained soil under undrained conditions, negative pore water pressure is generated due to the shear dilatation of the soil. Therefore, the pore water pressure data automatically stored by the data acquisition instrument is arranged, and the range of the shear dilatation zone is determined according to the area corresponding to the negative pore water pressure measured by each pore water pressure sensor embedded in the tooth surface of the cutter tooth.

[0052] The present application aims at the common problems in the current "iron plate sand" dredging construction. Firstly, a soil preparation subsystem with parameters equivalent to those of the site soil is proposed to restore the soil quality at the construction site, and the main indicators can all reach the indicator range of "iron plate sand". Secondly, a cutting subsystem is proposed to reproduce the actual situation of the rake tooth cutting the soil, including the cutting speed, cutting angle, and soil cutting thickness, which can all be consistent with the site. Thirdly, a measurement subsystem is proposed to measure the pore water pressure value generated during the cutting process of the rake tooth, and to store it in real time, providing a data source for the determination of the shear dilatation zone. In addition, a control subsystem is proposed to realize the automatic control of the cutting process of the rake tooth, and to ensure its accuracy.

[0053] The application can truly reproduce the actual process of tooth cutting soil in the construction site, and a series of model experiments are carried out through the experimental system to measure the distribution of negative pore water pressure along the tooth surface, and the distribution range of the shear dilation zone along the tooth surface in the soil cutting process is determined according to the experimental results, which further provides a basis for actively supplementing water to the shear dilation zone to reduce the shear dilation effect and thus reduce the cutting resistance of the tooth.

[0054] The application is suitable for dense silt and silty sand with relative density greater than 2 / 3 and standard penetration number greater than 30N, i.e. the soil commonly known as "iron plate sand", which shows shear dilation when the soil needs to be cut by the tooth.

[0055] The application is suitable for dredging engineering, and is used for determining the range of the shear dilation zone formed on the tooth surface in the dredging process of dense fine-grained soil, and providing a basis for actively supplementing water to the shear dilation zone to reduce the shear dilation effect and thus reduce the cutting resistance of the tooth.

[0056] The application can simulate different soil qualities in the construction site, simulate the actual situation of the prototype tooth cutting soil, and simultaneously perform real-time measurement of the pore water pressure and real-time collection of experimental data.

[0057] The application has the following beneficial effects: close to the engineering practice, high integration degree, remote automatic control, real-time display and automatic saving of data. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is a structural schematic diagram of the application,

[0059] Figure 2 is a structural schematic diagram of the preparation subsystem in the application,

[0060] Figure 3 is a structural schematic diagram of the suction device in the application,

[0061] Figure 4 is a structural schematic diagram of the gas-water separation device in the application,

[0062] Figure 5 is a structural schematic diagram of the preparation pool in the application,

[0063] Figure 6 is a structural schematic diagram of the supply device in the application,

[0064] Figure 7 is a structural schematic diagram of the cutting subsystem in the application,

[0065] Figure 8 is a structural diagram of the cutting connection device in the present application,

[0066] Figure 9 is a structural diagram of the traction system in the present application,

[0067] Figure 10 is a structural diagram of the measurement subsystem in the present application,

[0068] Figure 11 is a diagram of the control subsystem in the present application,

[0069] Figure 12 is a connection diagram of the control device connecting the force sensor, the water pressure sensor, the power system, the angle adjusting hydraulic cylinder and the height adjusting hydraulic cylinder through the data acquisition instrument and the traction controller in the present application,

[0070] Figure 13 is a control flowchart of the traction controller in the present application,

[0071] Figure 14 is a diagram of the shear dilation zone range of the tooth surface determined in the present application.

[0072] The component names corresponding to the reference signs are as follows:

[0073] 1: preparation subsystem,

[0074] 11: suction device,

[0075] 111: vacuum pump,

[0076] 112: suction gas pipe,

[0077] 113: suction valve,

[0078] 12: gas-water separation device,

[0079] 121: separation valve,

[0080] 122: gas-water separation tank,

[0081] 123: water body,

[0082] 124: separation gas pipe,

[0083] 125: vacuum gauge,

[0084] 13: preparation pool,

[0085] 131: side wall,

[0086] 132: base,

[0087] 133: gravel,

[0088] 134: non-woven fabric,

[0089] 135: filter screen,

[0090] 136: sealing film,

[0091] 137: joint,

[0092] 138: film outlet device,

[0093] 139: drainage plate,

[0094] 14: supply device,

[0095] 141: water supply pipe,

[0096] 142: supply valve,

[0097] 143: water tank,

[0098] 144: airless water,

[0099] 15: vibrating compaction device,

[0100] 16: leveling device,

[0101] 2: cutting subsystem,

[0102] 21: cutting tooth,

[0103] 211: tooth surface,

[0104] 22: tooth seat,

[0105] 23: force sensor,

[0106] 24: cutting connection device,

[0107] 241: cutting connection plate,

[0108] 242: cutting connection frame,

[0109] 243: cutting connection arm,

[0110] 25: angle adjustment hydraulic cylinder,

[0111] 26: height adjustment hydraulic cylinder,

[0112] 27: trolley,

[0113] 28: track,

[0114] 29: traction system,

[0115] 291: steel wire rope,

[0116] 292: power system,

[0117] 293: traction controller,

[0118] 294: rack,

[0119] 3: measurement subsystem,

[0120] 31: water-permeable stone,

[0121] 32: water body,

[0122] 33: water pressure sensor,

[0123] 34: silica gel,

[0124] 35: communication cable,

[0125] 4: control subsystem,

[0126] 41: data acquisition instrument,

[0127] 42: data line,

[0128] 43: control device,

[0129] 5: soil body. DETAILED DESCRIPTION

[0130] The present application is further illustrated by the following specific examples.

[0131] Example 1

[0132] An experimental system for determining the range of the shear dilation zone of dense fine-grained soil includes a preparation subsystem 1, a cutting subsystem 2, a measurement subsystem 3, and a control subsystem 4, as shown in Figure 1 The specific structure is as follows:

[0133] The preparation subsystem 1 is arranged on the ground, the cutting subsystem 2 is arranged on the preparation subsystem 1, the measurement subsystem 3 is arranged on the cutting subsystem 2, and the control subsystem 4 is connected with the cutting subsystem 2.

[0134] The preparation subsystem 1 is as shown in Figure 2 The preparation subsystem 1 includes a suction device 11, a gas-water separation device 12, a preparation pool 13, a supply device 14, a vibration compaction device 15, and a leveling device 16, and is used to prepare various types of dense fine-grained soil including dense fine sand, dense silty sand, and dense silt, etc.

[0135] Preparation pool 13 is located on the ground and contains soil 5. Suction device 11 and air-water separation device 12 are both located on one side of preparation pool 13, and supply device 14 is located on the other side of preparation pool 13. Vibration compaction device 15 and leveling device 16 are both located above soil 5 in preparation pool 13. Suction device 11 draws air from soil 5 in preparation pool 13 through air-water separation device 12. Air-water separation device 12 separates the moisture contained in the air drawn out by suction device 11. Supply device 14 outputs de-aired water 144 to preparation pool 13. Vibration compaction device 15 vibrates and compacts soil 5 in preparation pool 13. Leveling device 16 smooths the surface of soil 5 in preparation pool 13.

[0136] Suction device 11 Figure 3 As shown: The suction device 11 includes a vacuum pump 111, a suction gas supply pipe 112, and a suction valve 113. The inlet end of the vacuum pump 111 is... Figure 3 The IN end of the vacuum pump 111 is connected to the gas-liquid separator 12 via the suction and gas delivery pipe 112, and the outlet end of the vacuum pump 111 is... Figure 3 At the OUT end of the gas supply pipe 112, a suction valve 113 is connected in series.

[0137] Gas-water separator 12 Figure 4 As shown: The gas-water separation device 12 includes a separation valve 121, a gas-water separation tank 122, a separation gas delivery pipe 124, and a vacuum gauge 125. The outlet of the gas-water separation tank 122 is connected to the suction gas delivery pipe 112, and the inlet of the gas-water separation tank 122 is connected to the preparation tank 13 through the separation gas delivery pipe 124. Water 123 is collected in the gas-water separation tank 122. Air in the soil 5 in the preparation tank 13 is drawn in by the vacuum pump 111 and first enters the gas-water separation tank 122 through the separation gas delivery pipe 124. Moisture in the air collects at the bottom of the gas-water separator 122 and accumulates into water body 123. The air with separated moisture is discharged by the vacuum pump 111 through the suction pipe 112. Separation valves 121 are respectively provided on the upper part and bottom of the side of the gas-water separator 122. Separation valves 121 are also connected in series on the separation pipe 124. A vacuum gauge 125 is provided on the top of the gas-water separator 122. The gas-water separation device 12 is used to separate the gas-water mixture extracted by the vacuum pump 111 to avoid damaging the vacuum pump 111.

[0138] Preparation pool 13 Figure 5As shown in the figure, the preparation pool 13 includes a side wall 131, a foundation 132, gravel 133, non-woven fabric 134, filter screen 135, sealing film 136, joint 137, membrane outlet device 138 and drainage plate 139. The foundation 132 is built on the ground, and the side wall 131 is built around the foundation 132. Both the foundation 132 and the side wall 131 are of a turning masonry structure or a concrete structure. The inner and outer surfaces of the foundation 132 and the side wall 131 are coated with a waterproof layer. The top surface of the foundation 132 and the lower part of the inner surface of the side wall 131 are paved with gravel 133 as a drainage and exhaust passage. The top surface of the gravel 133 is paved with non-woven fabric 134 and filter screen 135 from bottom to top as a filter layer. The soil body 5 used for the experiment is stacked on the filter screen 135. The top surface of the soil body 5 is paved with filter screen 135, non-woven fabric 134, drainage plate 139 and sealing film 136 from bottom to top, thereby forming a closed space around the soil body 5. The drainage plate 139 is connected to the membrane outlet device 138 through the joint 137. The membrane outlet device 138 is connected to the separated gas conveying pipe 124. The length of the inner cavity of the preparation pool 13 is not less than 40 m.

[0139] The supply device 14 is as shown in the figure. Figure 6 As shown in the figure, the supply device 14 includes a water conveying pipe 141, a supply valve 142 and a water tank 143. The water tank 143 contains still water 144. The water tank 143 is connected to the preparation pool 13 through the water conveying pipe 141 at the bottom to input the still water 144 into the preparation pool 13. The supply valve 142 is connected in series on the water conveying pipe 141 to control the start and stop of the water conveying and the water volume.

[0140] The vibration and compaction device 15 is used to further compact the soil body 5 after it is extruded by the vacuum pump 111, so as to reduce the voids inside the soil body 5 and increase the compactness of the soil body 5.

[0141] The leveling device 16 is fixed on the truss of the trolley 27. When the trolley 27 moves, the leveling device 16 is driven to level the surface of the soil body 16.

[0142] The cutting subsystem 2 is as shown in the figure. Figure 7 As shown in the figure, the cutting subsystem 2 includes a cutter tooth 21, a tooth seat 22, a force sensor 23, a cutting connection device 24, an angle adjusting hydraulic cylinder 25, a height adjusting hydraulic cylinder 26, a trolley 27, a track 28 and a traction system 29. The cutting subsystem 2 is used to dynamically cut the soil body,

[0143] The traction system 29 is arranged on both sides of the top of the preparation pool 13, the track 28 is fixed above the preparation pool 13, the trolley 27 is movably arranged on the track 28 through the wheels at the bottom, the traction system 29 is connected to both ends of the trolley 28, the top end of the cutting connecting device 24 and the height adjusting hydraulic cylinder 26 are sequentially fixed at the bottom of the trolley 27, the moving end of the piston rod of the height adjusting hydraulic cylinder 26 is connected to the middle part of the cutting connecting device 24, the cylinder body of the angle adjusting hydraulic cylinder 25 is fixed at the front part of the cutting connecting device 24, the moving end of the piston rod of the angle adjusting hydraulic cylinder 25 is connected to the front part of the cutting connecting device 24, the tooth seat 22 is fixed at the top end of the cutting connecting device 24, the cutter tooth 21 and the force sensor 23 are both fixed on the tooth seat 22, the trolley 27 moves along the track 28 under the traction of the traction system 29, thereby driving the cutter tooth 21 to linearly cut the soil body 5;

[0144] The cutter tooth 21 is fixed on the tooth seat 22, the force sensor 23 is fixed on the tooth seat 22 through the flange joint, and the force sensor 23 synchronously measures the cutting resistance when the cutter tooth 21 cuts the soil body 5;

[0145] The cutting connecting device 24 is as shown in Figure 8 The cutting connecting device 24 includes the cutting connecting device 24, the cutting connecting plate 241, the cutting connecting frame 242 and the cutting connecting arm 243, one end of the cutting connecting plate 241 is connected to the force sensor 23 through the bolt-nut assembly, the other end of the cutting connecting plate 241 is connected to one end of the cutting connecting frame 242 through the bolt-nut assembly, the other end of the cutting connecting frame 242 is rotatably arranged at one end of the cutting connecting arm 243 through the hinge, and the other end of the cutting connecting arm 243 is rotatably arranged on the trolley 27 through the hinge;

[0146] The cylinder body of the angle adjusting hydraulic cylinder 25 is fixed on the cutting connecting arm 243, the moving end of the piston rod of the angle adjusting hydraulic cylinder 25 is rotatably connected to the cutting connecting frame 242 through the hinge, the cutting connecting frame 242 is driven to rotate through the extension and contraction of the piston rod of the angle adjusting hydraulic cylinder 25, thereby adjusting the cutting angle of the cutter tooth 21;

[0147] The cylinder body of the height adjusting hydraulic cylinder 26 is fixed at the bottom of the trolley 27, the moving end of the piston rod of the height adjusting hydraulic cylinder 26 is rotatably connected to the cutting connecting arm 243 through the hinge, the cutter tooth 21 is driven to move up and down through the extension and contraction of the piston rod of the height adjusting hydraulic cylinder 26, thereby adjusting the height of the cutter tooth 21, and adjusting the thickness of the cutter tooth 21 cutting the soil body 5;

[0148] The traction system 29 is as shown in Figure 9As shown in the figure: the traction system 29 includes a steel wire rope 291, a power system 292, a traction controller 293 and a rack 294, the rack 294 is fixed on one side of the preparation pool 13, the power system 292 and the traction controller 293 are both arranged on the rack 294, the traction controller 293 is connected with the power system 292, the angle adjusting hydraulic cylinder 25 and the height adjusting hydraulic cylinder 26 through signal lines respectively, the traction controller 293 is also connected with the control device 43 through a signal line, the steel wire rope 291 is tied on both sides of the trolley 27 after being drawn out from the power system, the power system 292 selects a winch or an electric hoist, the traction controller 293 selects a programmable controller, a single-chip microcomputer or a microcomputer, and the traction controller 293 adjusts the direction and speed of the traction trolley 27 by controlling the power system 292 under the instruction of the control device 43.

[0149] The measurement subsystem 3 is as shown in the figure: Figure 10 As shown in the figure: the measurement subsystem 3 includes a water-permeable stone 31, a water pressure sensor 33, silica gel 34 and a communication cable 35, the measurement subsystem 3 is used to measure the pore water pressure at each position of the interface between the cutting teeth 21 and the soil body 5 in real time during the cutting of the soil body 5,

[0150] The water pressure sensor 33 is arranged in the hole drilled by the cutting teeth 21 in the soil body 5 and is fixed by the silica gel 34, one end of the water pressure sensor 33 is provided with the communication cable 35 which is drawn out from the hole, the other end of the water pressure sensor 33 is provided with the water-permeable stone 31, the upper surface of the water-permeable stone 31 is flush with the cutting teeth 21, and the water body 32 bearing pressure in the soil body 5 is between the lower surface of the water-permeable stone 31 and the water pressure sensor 33, the water pressure sensor 33 selects a miniature pressure sensor with a diameter not greater than 5 mm and a thickness not greater than 1 mm;

[0151] The control subsystem 4 is as shown in the figure: Figure 11 As shown in the figure: the control subsystem 4 includes a data acquisition instrument 41, a data line 42 and a control device 43, the control subsystem 4 is used to automatically collect and store the pore water pressure data generated during the cutting of the soil body 5 by the cutting teeth 21,

[0152] The communication cable 35 at one end of the water pressure sensor 33 is connected with the data acquisition instrument 41, the force sensor 23 is also connected with the data acquisition instrument 41 through the communication cable 35, the data acquisition instrument 41 is connected with the control device 43 through the data line 42, and the control device 43 is also connected with the cutting subsystem 2 through the data line 42, and the control device 43 is provided with a parameter setting module, a cutting control module, an acquisition control module and a data processing module;

[0153] The control device 43 selects a microcomputer;

[0154] The control device 43 controls the power system 292, the angle adjusting hydraulic cylinder 25 and the height adjusting hydraulic cylinder 26 through the traction controller 293 according to the set parameters, so as to control the cutter teeth 21 to reciprocate according to the set parameters to cut the soil 5. The data acquisition instrument 41 collects the cutting resistance value measured by the force sensor 23 and the pore water pressure value measured by the water pressure sensor 33 in real time according to the set parameters and transmits them to the controller 43. The controller 43 stores the received cutting resistance value and pore water pressure value. The controller 43 can also transmit the cutting resistance value and pore water pressure value to other electronic devices through the network. After the cutting reaches the set requirement, the control device 43 controls the power system 292, the angle adjusting hydraulic cylinder 25 and the height adjusting hydraulic cylinder 26 to stop running and return to the initial position through the traction controller 293. The control device 43 then processes the received cutting resistance value and pore water pressure value.

[0155] The connection relationship of the control device 43, the data acquisition instrument 41 and the traction controller 293, the force sensor 23, the water pressure sensor 33, the power system 292, the angle adjusting hydraulic cylinder 25 and the height adjusting hydraulic cylinder 26 is as shown in FIG. 4. Figure 12

[0156] When the embodiment is used, the following steps are implemented:

[0157] S1. Soil preparation: Put the soil 5 into the preparation pool 13. The air in the soil 5 in the preparation pool 13 is sucked by the vacuum pump 111. The water in the air is first input into the air-water separation tank 122 through the separation air input pipe 124. The water in the air is collected in the lower part of the air-water separation tank 122 to form a water body 123. The air separated from the water is discharged by the vacuum pump 111 through the suction air input pipe 112. The water tank 143 is connected to the preparation pool 13 through the bottom water input pipe 141 to input the air-free water 144 into the preparation pool 13.

[0158] The soil 5 put into the preparation pool 13 is dug from the excavation construction site. The impurities (such as stones, garbage, branches, etc.) in the soil 5 are removed to ensure the uniformity of the soil 5. The indicators of the soil 5 put into the preparation pool 13 should be basically consistent with those of the soil in the excavation construction site.

[0159] S2. Setting: In the maintenance mode of the trolley 27, the control device 43 controls the power system 292 to perform zero correction on the trolley 27 and the steel wire rope 291 respectively through the traction controller 293. The control device 43 sets the cutting speed of the cutter teeth 22, the acquisition frequency of the force sensor 23 and the acquisition frequency of the water pressure sensor 33 through the parameter setting module. The frequency converter of the power system 292 is powered on to make the frequency converter in standby state. At the same time, it is ensured that the brake and tensioning hydraulic system of the traction system 29 are normal.

[0160] ​S3. Cutting: the cutting control module of the control device 43 controls the power system 292, the angle adjusting hydraulic cylinder 25 and the height adjusting hydraulic cylinder 26 through the traction controller 293 respectively, controls the cutting connecting frame 242 to rotate through the extension and retraction of the piston rod of the angle adjusting hydraulic cylinder 25 to adjust the cutting angle of the cutter tooth 21, controls the cutter tooth 21 to move up and down through the extension and retraction of the piston rod of the height adjusting hydraulic cylinder 26 to adjust the height of the cutter tooth 21, thereby adjusting the thickness of the soil body 5 cut by the cutter tooth 21, and the trolley 27 moves along the track 28 under the traction of the traction system 29, thereby driving the cutter tooth 21 to linearly cut the soil body 5 at a set cutting speed;

[0161] The moving speed of the cutter tooth 21 when cutting the soil body 5 is not greater than 3 m / s, and the fluctuation amplitude of the moving speed is not greater than 5%, and during cutting, the first 5 m is an acceleration section in which the speed increases from zero to the moving speed, and the last 5 m is a deceleration section in which the speed decreases from the moving speed to zero, and the cutting section of the moving speed is between the acceleration section and the deceleration section, and the length of the cutting section is not less than 30 m;

[0162]

[0163] S5. Acquisition: the acquisition control module of the control device 43 receives and stores the cutting resistance value measured by the force sensor 23 and the pore water pressure value measured by the water pressure sensor 33 at a frequency of once per 1 mm of running of the cutter tooth 21 through the data acquisition instrument 41;

[0164] S6. Analysis: the data processing module of the control device 43 determines the shear dilation zone range according to the received cutting resistance value and pore water pressure value, and the specific steps are as follows:

[0165] Firstly, the positions where the measured pore water pressure is positive are marked with "+" and the positions where the measured pore water pressure is negative are marked with "-"; secondly, for the regions adjacent to the positive and negative values, the difference is processed to obtain the positions where the pore water pressure is 0; thirdly, the positions where the pore water pressure is 0 are plotted as data points on the plan view of the tooth surface 211 of the cutter tooth 21; and finally, the points where the pore water pressure is 0 are connected into a line, which is the boundary line between the shear dilation zone and the non-shear dilation zone, and the region where the pore water pressure value is negative is the finally determined shear dilation zone range;

[0166] S7. Reset: the trolley 27 is stopped to stop the cutting of the soil body 5 by the cutter tooth 21, and then the trolley 27 is retreated to the initial zero position at a set speed.

[0167] In the above steps, S2-S7 are as shown in Figure 13

[0168] ​​The specific method and process of the above difference processing are as follows:

[0169] Using the present embodiment, for fine sand with a standard penetration hammer number N of 32, under the working conditions of a cutting angle a = 45°, a cutting speed v = 0.5 m / s, and a cutting thickness h = 0.1 m, the pore pressure values of the cutting tooth 21 surface collected are shown in Table 1, and the shear dilation zone range determined is shown in Figure 14 Figure 14 The shear dilation zone is shown in the middle SD.

[0170] Table 1 shows that the measured pore water pressure values are basically symmetrical along the central axis of the cutting tooth 21, and the pore pressure values gradually change from negative to positive from the tooth tip to the tooth seat 22 of the cutting tooth 21. According to the related theory of soil mechanics, saturated dense fine-grained soil will dilate when subjected to shear (cutting), which is macroscopically manifested as a negative pore water pressure value. According to the principle of effective stress, the generation of negative pore pressure will increase the effective stress, thereby making the soil more difficult to shear (cut) and excavate. Compared with other positions, the negative pore water pressure values at the central axis and the tooth tip are the largest, indicating that the soil at these positions has the strongest dilatancy.

[0171] Figure 14 It is shown that the shear dilation zone does not exist on the entire tooth surface 211 of the cutting tooth 21, but mainly exists in the lower half of the cutting tooth 21 and near the position close to the central axis of the cutting tooth 21. The shear dilation zone is in the shape of a sharp cone and is basically symmetrical along the central axis of the cutting tooth 21.

[0172] Table 1:

[0173] ​

Claims

1. An experimental system for determining the range of the shear dilation zone of a dense fine-grained soil, characterized by: The preparation subsystem (1), the cutting subsystem (2), the measurement subsystem (3) and the control subsystem (4) are arranged on the ground, the cutting subsystem (2) is arranged on the preparation subsystem (1), the measurement subsystem (3) is arranged on the cutting subsystem (2), and the control subsystem (4) is connected with the measurement subsystem (3), The preparation subsystem (1) comprises a suction device (11), a gas-water separation device (12), a preparation pool (13), a supply device (14), a vibration and compaction device (15) and a leveling device (16), The preparation pool (13) is arranged on the ground, the soil body (5) is arranged in the preparation pool (13), the suction device (11) and the gas-water separation device (12) are arranged on one side of the preparation pool (13), the supply device (14) is arranged on the other side of the preparation pool (13), the vibration and compaction device (15) and the leveling device (16) are arranged above the soil body (5) in the preparation pool (13), the suction device (11) sucks the air in the soil body (5) in the preparation pool (13) through the gas-water separation device (12), the gas-water separation device (12) separates the water contained in the air sucked by the suction device (11), the supply device (14) outputs the gas-free water (144) to the preparation pool (13), the vibration and compaction device (15) vibrates and compacts the soil body (5) in the preparation pool (13), and the leveling device (16) levels the surface layer of the soil body (5) in the preparation pool (13); The cutting subsystem (2) comprises a cutter tooth (21), a tooth seat (22), a force sensor (23), a cutting connecting device (24), an angle adjusting hydraulic cylinder (25), a height adjusting hydraulic cylinder (26), a trolley (27), a track (28) and a traction system (29), The traction system (29) is arranged on both sides of the top of the preparation pool (13), the track (28) is fixed above the preparation pool (13), the trolley (27) is movably arranged on the track (28) through the wheels at the bottom, the traction system (29) is connected to both ends of the trolley (28), the top end of the cutting connecting device (24) and the height adjusting hydraulic cylinder (26) are sequentially fixed at the bottom of the trolley (27), the moving end of the piston rod of the height adjusting hydraulic cylinder (26) is connected to the middle part of the cutting connecting device (24), the cylinder body of the angle adjusting hydraulic cylinder (25) is fixed at the front part of the cutting connecting device (24), the tooth seat (22) is fixed at the top end of the cutting connecting device (24), and the cutter tooth (21) and the force sensor (23) are both fixed on the tooth seat (22); The measurement subsystem (3) comprises a water-permeable stone (31), a water pressure sensor (33), silica gel (34) and a communication cable (35), The water pressure sensor (33) is arranged in the hole drilled by the cutter tooth (21) in the soil body (5) and is fixed by the silica gel (34), one end of the water pressure sensor (33) is provided with the communication cable (35) which is arranged to pass out of the hole, the other end of the water pressure sensor (33) is provided with the water-permeable stone (31), the upper surface of the water-permeable stone (31) is flush with the cutter tooth (21), and the water body (32) in the soil body (5) is arranged between the lower surface of the water-permeable stone (31) and the water pressure sensor (33) to bear pressure. The control subsystem (4) comprises a data acquisition instrument (41), a data line (42) and a control device (43), The water pressure sensor (33) is connected to the data acquisition instrument (41) through a communication cable (35), and the force sensor (23) is also connected to the data acquisition instrument (41) through the communication cable (35); the data acquisition instrument (41) is connected to the control device (43) through the data line (42), and the control device (43) is also connected to the cutting subsystem (2) through the data line (42); the control device (43) is provided with a parameter setting module, a cutting control module, an acquisition control module and a data processing module.

2. The experimental system for determining the range of the shear dilation zone of a dense fine-grained soil according to claim 1, characterized in that: In the preparation subsystem (1): The suction device (11) comprises a vacuum pump (111), a suction gas delivery pipe (112) and a suction valve (113); the suction gas delivery pipe (112) is connected to the air-water separation device (12) through the suction valve (113); The air-water separation device (12) comprises a separation valve (121), an air-water separation tank (122), a separation gas delivery pipe (124) and a vacuum gauge (125); the air-water separation tank (122) is connected to the suction gas delivery pipe (112); the air-water separation tank (122) is connected to the preparation pool (13) through the separation gas delivery pipe (124); the air-water separation tank (122) is provided with the water body (123); the air-water separation tank (122) is provided with the separation valve (121) on the upper part and the bottom part of the side surface; the separation gas delivery pipe (124) is also provided with the separation valve (121); the air-water separation tank (122) is provided with the vacuum gauge (125) on the top part; The preparation pool (13) comprises a side wall (131), a foundation (132), gravel (133), non-woven fabric (134), a filter screen (135), a sealing film (136), a joint (137), a membrane outlet device (138) and a drainage plate (139); the foundation (132) is built on the ground; the side wall (131) is built around the foundation (132); the foundation (132) and the side wall (131) are of a turn-built structure or a concrete structure; the inner and outer surfaces of the foundation (132) and the side wall (131) are coated with a waterproof layer; the top surface of the foundation (132) and the lower part of the inner surface of the side wall (131) are paved with the gravel (133); the top surface of the gravel (133) is paved with the non-woven fabric (134) and the filter screen (135) from bottom to top as a filter layer; the soil body (5) used for the experiment is stacked on the filter screen (135); the top surface of the soil body (5) is paved with the filter screen (135), the non-woven fabric (134), the drainage plate (139) and the sealing film (136) from bottom to top; the drainage plate (139) is connected to the membrane outlet device (138) through the joint (137); the membrane outlet device (138) is connected to the separation gas delivery pipe (124); the inner cavity of the preparation pool (13) has a length of not less than 40 m; The supply device (14) comprises a water pipe (141), a supply valve (142) and a water tank (143), the water tank (143) containing water (144), the water tank (143) being connected to the preparation pool (13) through the water pipe (141) at the bottom, and the supply valve (142) being connected in series on the water pipe (141); The vibration and compaction device (15) is used for further tamping the soil body (5) after the soil body (5) is extruded by the vacuum pump (111), so that the internal voids of the soil body (5) are reduced, thereby increasing the compactness of the soil body (5); The leveling device (16) is fixed on the truss of the trolley (27), and the trolley (27) drives the leveling device (16) to level the surface of the soil body (5) when the trolley (27) moves.

3. The experimental system for determining the range of the shear dilation zone of the compacted fine-grained soil according to claim 2, characterized in that: In the cutting subsystem (2): The cutter tooth (21) is fixed on the cutter holder (22), and the force sensor (23) is fixed on the cutter holder (22) through a flange joint; The cutting connecting device (24) comprises a cutting connecting device (24), a cutting connecting plate (241), a cutting connecting frame (242) and a cutting connecting arm (243), one end of the cutting connecting plate (241) is connected to the force sensor (23) through a bolt-nut assembly, the other end of the cutting connecting plate (241) is connected to one end of the cutting connecting frame (242) through a bolt-nut assembly, the other end of the cutting connecting frame (242) is rotatably arranged on one end of the cutting connecting arm (243) through a hinge, and the other end of the cutting connecting arm (243) is rotatably arranged on the trolley (27) through a hinge; The cylinder body of the angle adjusting hydraulic cylinder (25) is fixed on the cutting connecting arm (243), and the moving end of the piston rod of the angle adjusting hydraulic cylinder (25) is rotatably connected to the cutting connecting frame (242) through a hinge; The cylinder body of the height adjusting hydraulic cylinder (26) is fixed on the bottom of the trolley (27), and the moving end of the piston rod of the height adjusting hydraulic cylinder (26) is rotatably connected to the cutting connecting arm (243) through a hinge; The traction system (29) comprises a steel wire rope (291), a power system (292), a traction controller (293) and a rack (294), the rack (294) is fixed on one side of the preparation pool (13), the power system (292) and the traction controller (293) are arranged on the rack (294), the traction controller (293) is connected to the power system (292), the angle adjusting hydraulic cylinder (25) and the height adjusting hydraulic cylinder (26) through signal lines respectively, the traction controller (293) is also connected to the control device (43) through a signal line, and the steel wire rope (291) is tied to the two sides of the trolley (27) after being led out from the power system.

4. The experimental system for determining the range of the shear dilation zone of the compacted fine-grained soil according to claim 3, characterized in that: The power system (292) is selected from a winch or an electric hoist, and the traction controller (293) is selected from a programmable controller, a single-chip microcomputer or a microcomputer; The water pressure sensor (33) is selected from a micro pressure sensor; The control device (43) is selected from a microcomputer; The control device (43) controls the power system (292), the angle adjusting hydraulic cylinder (25) and the height adjusting hydraulic cylinder (26) through the traction controller (293) according to the set parameters, so as to control the cutter teeth (21) to reciprocate according to the set parameters to cut the soil body (5), the data acquisition instrument (41) collects the cutting resistance value measured by the force sensor (23) and the pore water pressure value measured by the water pressure sensor (33) in real time according to the set parameters and transmits them to the control device (43), the control device (43) stores the received cutting resistance value and pore water pressure value, after the cutting reaches the set requirement, the control device (43) controls the power system (292), the angle adjusting hydraulic cylinder (25) and the height adjusting hydraulic cylinder (26) to stop running and return to the initial position through the traction controller (293), and the control device (43) subsequently processes the received cutting resistance value and pore water pressure value.

5. The method of using the experimental system for determining the range of the shear dilation zone of a dense fine-grained soil according to claim 4, wherein: The following steps are implemented: S1. Soil preparation: Put the soil body (5) into the preparation pool (13), the air in the soil body (5) in the preparation pool (13) is sucked by the vacuum pump (111), first input into the air-water separation tank (122) through the separation air conveying pipe (124), the water in the air collects in the lower part of the air-water separation tank (122) to form a water body (123), the air separated from the water is discharged by the vacuum pump (111) through the suction air conveying pipe (112), and the water tank (143) is connected with the preparation pool (13) through the bottom water conveying pipe (141) to input the air-free water (144) into the preparation pool (13); S2. Setting: In the maintenance mode, the control device (43) controls the power system (292) to respectively implement zero correction on the trolley (27) and the steel wire rope (291) through the traction controller (293), the control device (43) sets the cutting speed of the cutter teeth (21), the acquisition frequency of the force sensor (23) and the acquisition frequency of the water pressure sensor (33) through the parameter setting module, and powers on the frequency converter of the power system (292) to make the frequency converter in standby state, while ensuring that the brake and tensioning hydraulic work of the traction system (29) are normal; S3. Cutting: The cutting control module of the control device (43) controls the power system (292), the angle adjusting hydraulic cylinder (25) and the height adjusting hydraulic cylinder (26) through the traction controller (293), drives the cutting connecting frame (242) to rotate through the extension and retraction of the piston rod of the angle adjusting hydraulic cylinder (25) to adjust the cutting angle of the cutter teeth (21), drives the cutter teeth (21) to move up and down through the extension and retraction of the piston rod of the height adjusting hydraulic cylinder (26) to adjust the height of the cutter teeth (21), so as to adjust the thickness of the cutter teeth (21) cutting the soil body (5), the trolley (27) moves along the track (28) under the traction of the traction system (29), thereby driving the cutter teeth (21) to linearly cut the soil body (5) at the set cutting speed; S4. Measurement: When the blade teeth (21) cut the soil body (5), the force sensor (23) synchronously measures the cutting resistance at a set acquisition frequency, and the water pressure sensor (33) synchronously measures the pore water pressure at the interface between the blade teeth (21) and the soil body (5) during the cutting process of the soil body (5); S5. Acquisition: The acquisition control module of the control device (43) receives and stores the cutting resistance value measured by the force sensor (23) and the pore water pressure value measured by the water pressure sensor (33) through the data acquisition instrument (41); S6. Analysis: The data processing module of the control device (43) determines the shear dilation zone range according to the received cutting resistance value and pore water pressure value, and the specific steps are as follows: Firstly, mark the positions where the measured pore water pressure is positive with "+" and the positions where the measured pore water pressure is negative with "-"; secondly, for the adjacent regions of positive and negative values, difference processing is performed to obtain the positions where the pore water pressure is zero; Then, plot the positions where the pore water pressure is zero as data points on the tooth surface (211) plane of the blade teeth (21); Finally, connect the points where the pore water pressure is zero to form a line, which is the boundary line between the shear dilation zone and the non-shear dilation zone, and the region where the pore water pressure value is negative is the finally determined shear dilation zone range; S7. Reset: The control device (43) controls the power system (292) through the traction controller (293) to stop the operation of the trolley (27) to stop the cutting of the blade teeth (21) on the soil body (5), and the piston rods of the angle adjusting hydraulic cylinder (25) and the height adjusting hydraulic cylinder (26) are retracted, and then the control device (43) controls the power system (292) through the traction controller (293) to retreat the trolley (27) to the initial zero position at a set speed.

6. The use method of the experimental system for determining the shear dilation zone range of dense fine-grained soil according to claim 5, characterized in that: In step S1, the soil body (5) placed in the preparation tank (13) is dug from the construction site, and impurities are removed to ensure the uniformity of the soil body (5); In step S3, the moving speed of the blade teeth (21) during cutting of the soil body (5) is not greater than 3 m / s, and the fluctuation amplitude of the moving speed is not greater than 5%, and during cutting, the initial 5 m is an acceleration section where the speed increases from zero to the moving speed, and the last 5 m is a deceleration section where the speed decreases from the moving speed to zero, and the length of the cutting section between the acceleration section and the deceleration section is not less than 30 m; In step S5, the acquisition control module of the control device (43) receives and stores the cutting resistance value measured by the force sensor (23) and the pore water pressure value measured by the water pressure sensor (33) at a frequency of 1 mm per run of the blade teeth (21).

Images