Static cone penetration test device and method for simultaneously sampling and measuring sensitivity of soft clay

Abstract

The invention discloses a static sounding test device for simultaneously sampling and measuring the sensitivity of soft clay. The static sounding test device mainly comprises a static sounding probe, a probe rod with a bayonet, a sampler and a vane test device arranged in the large-diameter short probe rod. When the static sounding probe penetrates into a certain depth, the probe rod with the buckle moves upwards along with the upper probe rod, the sampler keeps still under the action of friction force of surrounding soil, the sampler and the upper probe rod are locked through the spring lock, and when the upper probe rod penetrates into the soil downwards again, the sampler is pressed into the soil at the same time to complete sampling of undisturbed soil. A telescopic cross plate probe rod in the large-diameter short probe rod enables a cross plate head to stretch out in the horizontal direction, so that the peak value of the soft clay and the residual undrained shear strength are measured, and the sensitivity is determined. According to the device disclosed by the invention, an undisturbed soil sample can be obtained at a certain depth and the undrained shear strength and sensitivity of soft clay can be measured by utilizing a penetration device for a static sounding test without a drilling machine, the penetration device and a slurry protection wall.

Description

Technical Field

[0001] The invention belongs to the field of drilling sampling and in-situ testing of geotechnical engineering, and specifically relates to a test device and method capable of drilling sampling, measuring the sensitivity of soft clay and performing static penetration testing. Background Art

[0002] Before designing and constructing various engineering projects, it is necessary to first determine the physical and mechanical properties of the foundation soil through indoor tests or in-situ tests. Compared with indoor tests, in-situ tests have the advantages of being able to reflect the characteristics of rock and soil under natural stress states, having a large range of soil measurements, and having a short test cycle. The static penetration test uses quasi-static force to press a conical probe into the soil through a series of probes at a constant penetration rate. Based on the measured cone tip resistance, side wall friction, and pore water pressure, soil layer division, soil classification, and estimation of soil physical and mechanical indicators such as overconsolidation ratio, undrained shear strength, sand density, compression modulus, and consolidation coefficient can be performed. Due to its advantages of continuous testing, large amounts of test data, high efficiency, and high economy, the static penetration test is currently the most widely used in-situ test method in the field of geotechnical engineering. However, the static penetration test cannot drill soil samples, nor can it directly measure the undrained shear strength and sensitivity of soft clay.

[0003] When directly measuring the physical and mechanical properties of soil through indoor tests, it is first necessary to take undisturbed soil samples on site. Therefore, undisturbed soil sampling is a basic work in geotechnical engineering investigation. At present, thin-walled soil sampling devices are usually used for drilling sampling. The soil sampling device is quickly and continuously penetrated into the soil body by static pressure using drilling equipment. Therefore, drilling sampling usually requires a special drilling rig and penetration device, and it is also necessary to use mud wall protection. Therefore, it is necessary to combine the static penetration instrument with the soil sampling device, use the penetration device of the static penetration test to penetrate the soil sampling device into the soil body at a certain depth, and sample the undisturbed soil while conducting the static penetration test.

[0004] The sensitivity of soft clay refers to the ratio of the undrained shear strength of the original soil to its corresponding remolded soil. It can be used to evaluate the structural strength of the clay and can be determined through a cross-plate shear test. The cross-plate shear test is to apply torque to the cross-plate head inserted into the foundation soil so that the cross-plate head is twisted at an equal speed in the soil to form a cylindrical failure surface. By measuring the resistance torque at the time of soil failure and the final resistance torque, the peak and residual undrained shear strength of the soil can be obtained, and then the sensitivity of the soft clay can be calculated. However, when conducting a cross-plate shear test, it is also necessary to first drill a hole (pre-drilling or self-drilling). Therefore, it is necessary to combine the static penetration tester with the cross-plate shear tester, and use the penetration device of the static penetration test to penetrate the cross-plate shear tester into the soil at a certain depth, so as to measure the sensitivity of the soft clay while conducting the static penetration test. Summary of the invention

[0005] In view of the above-mentioned prior art, the present invention provides a static penetration test device and method that can simultaneously take samples and measure the sensitivity of soft clay. The present invention designs a sampler that can be attached to the outside of the static penetration probe rod and sets a cross-plate shear instrument inside the static penetration probe rod, so that the original soil sampling and the determination of the sensitivity of soft clay can be completed simultaneously when the static penetration test is performed. The test device of the present invention can use the penetration device of the static penetration test, and the original soil sample of the specified depth can be obtained without a drilling rig, a penetration device and a mud wall. By using static penetration testing to drill holes, the undrained shear strength and sensitivity of the soil at a certain depth can be measured without pre-drilling or self-drilling. Therefore, the device of the present invention can combine static penetration testing with drilling sampling and cross-plate shear testing, which can greatly improve the efficiency of geotechnical engineering investigation and reduce the cost of geotechnical engineering investigation, and has important practical engineering significance.

[0006] In order to solve the above technical problems, the present invention proposes a static penetration test device for simultaneously sampling and measuring the sensitivity of soft clay. The test device includes a probe rod and a sampler. The probe rod includes a static penetration probe rod, a large-diameter short probe rod, a middle-length probe rod and a static penetration probe probe coaxially connected from top to bottom; the outer diameter of the large-diameter short probe rod is consistent with the outer diameter of the sampler, and the outer diameter of the sampler is larger than the diameter of the static penetration probe probe.

[0007] The large-diameter short probe rod is provided with a radial groove for installing a cross-plate shearing instrument, a retractable cross-plate probe rod of the cross-plate shearing instrument is provided in the radial groove, a cross-plate head is provided at the head of the retractable cross-plate probe rod, a cross-plate shearing instrument side cover is provided at the notch of the radial groove, and a side cover shallow groove is provided at the upper end of the notch;

[0008] The middle long probe rod comprises a rod body and a probe rod buckle arranged at the lower end of the rod body, the probe rod buckle is a coaxial cylindrical structure connected to the bottom periphery of the rod body, a buckle inclined surface is arranged on the inner edge of the top of the cylinder, and a spring lock hole is arranged in the middle of the cylinder;

[0009] The sampler comprises a barrel and a sampler buckle arranged at the inner opening of the top and matched with the probe rod buckle, the barrel being provided with an air vent, the axial dimension of the inner wall of the sampler buckle is consistent with the cylinder depth of the probe rod buckle, the inner wall thickness of the sampler buckle is consistent with the reserved gap between the cylinder of the probe rod buckle and the rod body, a pair of spring lock mounting grooves are arranged on the outer wall of the sampler buckle, the barrel of the sampler is provided with an annular groove corresponding to the axial position of the spring lock mounting groove, a spring lock mounting hole aligned with the position of the spring lock mounting groove is arranged in the annular groove, and a spring lock is installed in the spring lock mounting groove and the spring lock mounting hole after the alignment; a detachable ring is arranged in the annular groove, and a boss aligned with the position of the spring lock mounting groove is arranged on the inner surface of the detachable ring, and after the detachable ring is installed, the boss abuts against the spring lock;

[0010] The probe rod is provided with a cable channel which passes through the static sounding probe rod, the large-diameter short probe rod and the middle-length probe rod. The cable and data line of the static sounding probe are led out from the cable channel. The rear wall of the radial groove is provided with a through hole which passes through the cable channel. The cable and data line of the retractable cross-plate probe rod of the cross-plate shear instrument are led out from the cable channel after passing through the through hole in the rear wall of the radial groove.

[0011] Furthermore, the static penetration test device for simultaneous sampling and determination of sensitivity of soft clay described in the present invention comprises:

[0012] The spring lock comprises a lock head, a spring is arranged inside the lock head, a spring lock inclined surface is arranged on the lower end surface of the lock head, and the spring lock inclined surface is consistent with the buckle inclined surface of the probe rod buckle.

[0013] The upper and lower ends of the large-diameter short probe rod are respectively connected to the static penetration probe rod and the middle long probe rod by welding, and the connection between the static penetration probe head and the middle long probe rod is threaded.

[0014] The bottom surface of the large-diameter short probe rod is the sampler load-bearing surface, the top surface of the sampler is the sampler force-bearing surface, and there is a clearance fit between the inner wall of the sampler barrel and the outer wall of the rod body of the middle long probe rod; when assembling the sampler, the sampler force-bearing surface is pressed against the sampler load-bearing surface.

[0015] The detachable circular ring is composed of two embracing semicircular rings, which are respectively denoted as semicircular ring A and semicircular ring B. A screw is preset on the open end face of the semicircular ring A, and a threaded hole coaxial with the screw is provided on the open end face of the semicircular ring B. When installing the detachable circular ring, align the bosses on the inner surfaces of the semicircular rings A and B with the spring locks, and then screw the screws into the opposite threaded holes.

[0016] The tests conducted using the static penetration test device for simultaneously sampling and measuring the sensitivity of soft clay proposed by the present invention include:

[0017] 1) Static penetration test: The probe rod is penetrated into the soil at a speed of 2 cm / s through the penetration equipment to measure the cone tip resistance, side wall friction resistance and pore water pressure of the soil at different depths;

[0018] 2) Cross-plate shear test: Move the probe rod upward, open the side cover of the cross-plate shear instrument, extend the retractable cross-plate probe rod, and extend the cross-plate head a certain distance in the horizontal direction; rotate the probe rod clockwise to make the cross-plate head generate torque until the torque data collection system shows a peak torque, measure the peak torque, and calculate the peak undrained shear strength; continue to rotate the probe rod clockwise for 6 circles, measure the final torque, and calculate the residual undrained shear strength; the ratio of the peak value to the residual undrained shear strength is the sensitivity of the soft clay; after the measurement is completed, shorten the retractable cross-plate probe rod, retract the cross-plate head into the large-diameter short probe rod, and close the side cover of the cross-plate shear instrument;

[0019] 3) Borehole sampling: After the probe rod reaches the sampling depth, stop penetrating and pull the probe rod upward. At this time, the sampler remains motionless under the action of the friction force of the surrounding soil; when the probe rod buckle of the probe rod moves upward to the position of the sampler buckle, the probe rod and the sampler are locked; the probe rod penetrates downward again, carrying the sampler downward into the soil, and the soil sample gradually enters the sampler; after the soil completely enters the sampler, the probe rod is moved upward and pulled upward together with the sampler; under the action of the friction force between the soil sample and the inner wall of the sampler and the negative pressure in the sampler, the soil sample moves upward with the sampler, thereby completing the sampling of the original soil;

[0020] Furthermore, in the static penetration test, the large-diameter short probe rod plays a role in expanding the hole and reducing the penetration force.

[0021] During the drilling sampling, the air holes on the sampler allow the gas in the sampler to flow out, thereby avoiding the generation of high air pressure in the sampler.

[0022] The combination of projects to complete the test is one of the following:

[0023] Only static penetration test is carried out;

[0024] Conduct static penetration test and cross plate shear test;

[0025] Conduct static penetration tests and borehole sampling;

[0026] Conduct static penetration test, cross plate shear test and drilling sampling.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Although the static penetration test can measure multiple data such as cone tip resistance, side wall friction resistance and pore water pressure, and then indirectly estimate the physical and mechanical parameters of the soil through empirical formulas, it cannot drill holes for sampling. The device of the present invention can obtain undisturbed soil samples during the static penetration test, which can be used for indoor tests to directly measure the physical and mechanical parameters of the soil.

[0029] (2) Although the static penetration test can indirectly estimate the undrained shear strength of the soil through the cone tip resistance, it cannot directly measure the undrained shear strength of the soil. The device of the present invention can perform a cross-plate shear test during the static penetration test to directly measure the undrained shear strength of soft clay.

[0030] (3) At present, drilling sampling usually requires a special drilling rig and a penetration device, and mud wall protection is also required. The present invention proposes a sampler that can be attached to the outside of the static penetration test rod, and the sampler is penetrated to a specified depth using the penetration device of the static penetration test. Without the need for a drilling rig, a penetration device and a mud wall protection, the original soil sample at the specified depth can be obtained.

[0031] (4) Currently, when conducting a cross-plate shear test, it is necessary to first pre-drill or self-drill. The present invention proposes a cross-plate shear instrument that can be set inside a static penetration probe rod. By using static penetration to drill holes, there is no need to pre-drill or self-drill. A cross-plate shear test can be performed at a specified depth to measure the undrained shear strength and sensitivity of soft clay.

[0032] (5) The present invention innovatively combines a static penetration tester, a sampler and a cross-plate shear tester together, which can obtain undisturbed soil samples during the static penetration test and directly measure the undrained shear strength and sensitivity of soft clay in situ. This can greatly improve the efficiency of geotechnical engineering investigation and reduce the cost of geotechnical engineering investigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the test device of the present invention;

[0034] Figure 2 yes Figure 1 The structural diagram of the probe and the probe rod shown in FIG.

[0035] Figure 3 yes Figure 1 The structural schematic diagram of the sampler shown in;

[0036] Figure 4 yes Figure 1 A cross-sectional view of a short probe with a large diameter as shown in FIG.

[0037] Figure 5 yes Figure 4 A side view of the large diameter short probe shown;

[0038] Figure 6 yes Figure 4 A cross-sectional view of a short probe with a large diameter in a state where the cross plate head is extended;

[0039] Figure 7 yes Figure 6 A side view of the large diameter short probe shown;

[0040] Figure 8 is a front cross-sectional view of the test device of the present invention in an unlocked state of the spring lock;

[0041] Fig. 9 is a front cross-sectional view of the spring lock in the test device of the present invention in a locked state;

[0042] Fig.10 yes Fig. 9 A top cross-sectional view of the spring lock in a locked state;

[0043] Fig.11 yes Fig.10 A top cross-sectional view of the semicircular ring A in the fixing ring shown in FIG.

[0044] Fig.12 yes Fig.11 A left side view of the semicircular ring A shown;

[0045] Fig.13 yes Fig.10 A top cross-sectional view of the semicircular ring B in the fixing ring shown in FIG.

[0046] Fig.14 yes Fig.13 A right side view of the semicircular ring B shown;

[0047] Fig.15 The present invention is a process of conducting a test using the test device of the present invention, wherein: (a) is the state of the test device penetrating into the soil, (b) is the state of the retaining cover 22 being opened, (c) is the state of the cross plate head 7 being extended, (d) is the state of the cross plate head being retracted, (e) is the state of the probe rod being pulled upward, (f) is the state of the sampling tube and the probe rod being locked by the bayonet, (g) is the state of the sampling tube being pressed into the soil, and (h) is the state of the soil entering the sampling tube.

[0048] In the figure:

[0049] 1-Large diameter short probe rod 2-Middle length probe rod 3-Sampler 4-Static penetration probe

[0050] 5-cable channel 6-retractable cross plate probe 61-through hole 7-cross plate head

[0051] 71- radial groove 72- shallow groove of side cover 8- bearing surface of sampler 9- probe rod buckle

[0052] 10- buckle slope 11- spring lock hole 12- reserved gap 13- sampler force surface

[0053] 14- spring lock 15- sampler buckle 16- spring lock slope 17- sampler buckle inner wall

[0054] 18-lock head 19-spring 20-vent hole 21-static penetration probe rod

[0055] 22-Cross plate shear instrument side cover 23-Removable ring 231-Semi-circular ring A

[0056] 232-semicircle ring B 233-screw 234-threaded hole 235-boss DETAILED DESCRIPTION

[0057] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention in any way.

[0058] like Figure 1 The present invention proposes a static penetration test device for simultaneously sampling and measuring the sensitivity of soft clay. The test device includes a probe rod and a sampler. The probe rod includes a static penetration probe rod 21, a large-diameter short probe rod 1, a middle-length probe rod 2 and a static penetration probe head 4 coaxially connected from top to bottom.

[0059] The upper and lower ends of the large-diameter short probe rod 1 are respectively connected to the static penetration probe rod 21 and the middle long probe rod 2 by welding, and the connection between the static penetration probe 4 and the middle long probe rod 2 is threaded.

[0060] like Figures 4 to 7 As shown, the large diameter short probe rod 1 is provided with a radial groove 71 for installing a cross plate shear instrument, a retractable cross plate probe rod 6 of the cross plate shear instrument is provided in the radial groove 71, a cross plate head 7 is provided at the head of the retractable cross probe rod 6, a cross plate head 7 is provided at the notch of the radial groove 72, a side cover 22 is provided at the upper end of the notch, a side cover shallow groove 72 is provided, and a through hole 61 is provided at the rear of the radial groove 71 for passing the cross plate shear instrument cable and data line.

[0061] In this embodiment, the retractable cross-plate probe rod 6 is composed of a plurality of sleeve rods of different diameters. When extended, the cross-plate head 7 can be extended a certain distance in the horizontal direction, so that the peak value and residual undrained shear strength of soft clay at a certain depth can be measured, and then the sensitivity of the soft clay at this depth can be determined.

[0062] like Figure 2As shown, the middle long probe rod 2 includes a rod body, the diameter of the rod body is the same as the diameter of the static penetration probe rod 21, and a probe rod buckle 9 is provided at the lower end of the rod body. The probe rod buckle 9 can be interlocked with the sampler buckle 15. The probe rod buckle 9 is a cylindrical structure connected to the bottom periphery of the rod body and coaxial, and a buckle slope 10 is provided on the inner edge of the top of the cylinder, and a spring lock hole 11 is provided in the middle of the cylinder.

[0063] like Figure 1 and Figure 3 As shown, the sampler 3 includes a barrel 31 and a sampler buckle 15 arranged at the inner mouth of the top and matched with the probe buckle 9, the barrel is provided with an air vent 20, the axial dimension of the inner wall 17 of the sampler buckle 15 is consistent with the cylinder depth of the probe buckle 9, the thickness of the inner wall 17 of the sampler buckle is consistent with the reserved gap 12 between the cylinder of the probe buckle 9 and the rod body, a pair of spring lock mounting grooves are provided on the outer wall of the sampler buckle 15, an annular groove corresponding to the axial position of the spring lock mounting groove is provided on the barrel of the sampler 3, a spring lock mounting hole aligned with the position of the spring lock mounting groove is provided in the annular groove, and the spring After the lock installation groove and the spring lock installation hole are aligned, a spring lock 14 is installed therein; the spring lock 14 includes a lock head 18, a spring 19 is provided inside the lock head 18, and a spring lock inclined surface 16 is provided on the lower end surface of the lock head 18. The spring lock inclined surface 16 is consistent in direction and coincides with the buckle inclined surface 10 of the probe rod buckle 9. When the spring lock inclined surface 16 and the buckle inclined surface 10 are in contact, the spring lock 14 will be squeezed horizontally, the spring 19 will be compressed, the lock head 18 will move inward, and the probe rod buckle 9 will gradually enter the sampler buckle 15. When the spring lock hole 11 is consistent in height with the lock head 18, the lock head 18 enters the spring lock hole 11, and the probe rod buckle 9 and the sampler buckle 15 are locked. Figure 8 The figure shows the unlocked state of the spring lock in the test device of the present invention. Fig. 9 and Fig.10 The figure shows the locking state of the spring lock in the test device of the present invention.

[0064] A detachable ring 23 is disposed in the annular groove, and a boss 235 is disposed on the inner surface of the detachable ring 23 to be aligned with the spring lock installation groove. After the detachable ring 23 is installed, the boss 23 abuts against the spring lock 14. Fig.10 , Fig.11 and Fig.13 As shown, the detachable ring 23 is composed of two semicircular rings that are embraced, and the two semicircular rings are respectively marked as semicircular ring A231 and semicircular ring B232. The open end surface of the semicircular ring A231 is preset with a screw 233, as shown in FIG. Fig.11 and Fig.12 The open end surface of the semicircular ring B232 is provided with a threaded hole 234 coaxial with the screw 233, as shown Fig.13 and Fig.14 As shown; when installing the detachable ring 23, align the boss 235 on the inner surface of the semicircular ring A231 and the semicircular ring B232 with the spring lock 14, and then screw the screw 233 into the threaded hole 234 on the opposite side, and fix the connection by the screw 233. After the sampling is completed, unscrew the screw 233, and the detachable ring 23 can be removed from the sampler 3, and then the probe rod buckle 9 and the sampler buckle 15 can be unlocked.

[0065] like Figure 1 , Figure 2 and Figure 3 As shown, the outer diameter of the sampler 3 is the same as the outer diameter of the large-diameter short probe rod 1, the bottom surface of the large-diameter short probe rod 1 is the sampler load-bearing surface 8, the top surface of the sampler 3 is the sampler load-bearing surface 13, and the inner wall of the barrel of the sampler 3 and the outer wall of the rod body of the middle long probe rod 2 are clearance fit; when assembling the sampler 3, the sampler load-bearing surface 13 is pressed against the sampler load-bearing surface 8.

[0066] like Figure 1 and Figure 2 As shown, the probe rod is provided with a cable channel 5 which passes through the static penetration probe rod 21 , the large-diameter short probe rod 1 and the middle-length probe rod 2 , and the cable of the static penetration probe head 4 is led out from the cable channel 5 .

[0067] When the static penetration test is carried out downward, the sampler 3 is attached to the outside of the middle long probe rod 2 with a buckle, and the sampler force surface 13 is in contact with the sampler force surface 8 at the bottom of the large-diameter short probe rod 1. When the large-diameter short probe rod 1 is carried out downward, the sampler 3 is carried out downward along with the large-diameter short probe rod 1. At the depth to be sampled, the large-diameter short probe rod 1 and the middle-length probe rod 2 with a buckle are pulled out upwards, and the sampler 3 remains stationary under the action of the friction force of the surrounding soil. When the probe rod buckle 9 of the middle-length probe rod 2 with a buckle moves upwards to the position of the sampler buckle 15, the probe rod buckle 9 can be interlocked with the sampler buckle 15. When the static penetration test is penetrated downwards again, the sampler 3 moves downwards along with the middle-length probe rod 2 with a buckle, and the soil can gradually enter the sampler 3. After the soil sample has completely entered, the middle-length probe rod 2 with a buckle and the sampler 3 with the soil sample are pulled out of the ground upwards, thereby completing the sampling of the original soil.

[0068] In the present embodiment, the number of the air holes 20 provided on the body of the sampler 3 is four evenly distributed along the same circumference. Specifically, the sampler 3 is provided with four air holes 20 at 30 cm below the sampler buckle 15. The air holes 20 are constructed as a funnel-shaped membrane made of rubber. When the inner air pressure is high, it will swell and an opening will appear, allowing the gas to flow out, thereby avoiding the generation of a high air pressure in the sampler 3 during sampling and preventing the soil sample from entering the sampler 3; when the outer air pressure is high, it will shrink to close the opening, preventing external soil samples and air from entering the sampling tube, thereby forming a negative pressure in the sampling tube when the probe rod is pulled upward, which helps the soil sample to move upward with the sampler 3.

[0069] In the present invention, the retractable cross-plate probe rod 6 and the cross-plate head 7 are arranged in a radial groove 71 of the large-diameter short probe rod 1. When the static penetration is penetrated downward, the large-diameter short probe rod 1 is penetrated downward along with the static penetration probe rod 21. When the depth at which the sensitivity of soft clay is to be measured is reached, the penetration is stopped, and the cross-plate shearing instrument side cover 22 is pulled upward along the side cover shallow groove 72, thereby opening the cross-plate shearing instrument side cover 22, extending the retractable cross-plate probe rod 6, and driving the cross-plate head 7 at its end to extend out of the large-diameter short probe rod 1, as shown in FIG. Figure 6 As shown. Then rotate the probe rod clockwise to generate torque on the cross plate head 7. The peak undrained shear strength can be calculated by the peak torque. Then continue to rotate clockwise for 6 turns, and then measure the torque to calculate the residual undrained shear strength. The ratio of the peak value to the residual undrained shear strength is the sensitivity of soft clay. After the measurement is completed, shorten the retractable cross plate probe rod 6, thereby driving the cross plate head 7 to retract into the large diameter short probe rod 1, and close the cross plate shear instrument side cover 22, as shown. Figure 4 shown.

[0070] The static penetration test for simultaneously sampling and determining the sensitivity of soft clay of the present invention is flexible to use, and can combine the static penetration test with drilling sampling and cross-plate shear test. By utilizing the penetration device of the static penetration test, the original soil sample at a certain depth can be obtained without a drilling rig, a penetration device and a mud wall; the undrained shear strength and sensitivity of soft clay at a specified depth can be determined without pre-drilling or self-drilling. Therefore, the device of the present invention can greatly improve the efficiency of engineering investigation and reduce the cost of engineering investigation. The test device of the present invention can perform the following tests: 1) only perform static penetration test, 2) perform static penetration test and cross-plate shear test at the same time, 3) perform static penetration test and drilling sampling at the same time, 4) perform static penetration test, cross-plate shear test and drilling sampling at the same time. The steps of each test are:

[0071] 1) Only conduct static penetration test, the steps are as follows:

[0072] 1-1) The static sounding probe 4 is fixedly connected to the middle long probe rod 2 with a buckle through threads, and the large diameter short probe rod 1 is welded to the middle long probe rod 2; the static sounding probe rod 21 is welded to the large diameter short probe rod 1, and the sampler 3 is installed on the outside of the middle long probe rod 2;

[0073] 1-2) Penetrating the static penetration probe 21 into the soil at a speed of 2 cm / s through the penetration equipment to measure the cone tip resistance, side wall friction resistance and pore water pressure of the soil at different depths;

[0074] 1-3) After the test is completed, the static penetration probe rod 21, the large-diameter short probe rod 1, the medium-length probe rod 2 and the static penetration probe head 4 are pulled out together to end the entire test;

[0075] Although the above steps are basically the same as those of a conventional static penetration test, since the outer diameter of the large-diameter short probe 1 in the test device of the present invention is larger than the outer diameter of the static penetration probe 21, it can play a role in expanding the hole, which helps to reduce the friction between the soil and the upper static penetration probe 21, thereby greatly reducing the penetration force.

[0076] 2) Conduct static penetration test and cross plate shear test simultaneously, the steps are as follows:

[0077] 2-1) Carry out static penetration test in the same manner as in steps 1-1) and 1-2);

[0078] 2-2) The static penetration probe rod 21 is penetrated into the soil at a speed of 2 cm / s by the penetration equipment, and the penetration is stopped after reaching the specified depth, and a cross-plate shear test is performed;

[0079] 2-3) Move the cross-plate shear instrument side cover 22 upward to open it, extend the retractable cross-plate probe 6, and extend the cross-plate head 7 horizontally for a certain distance; rotate the probe in a clockwise direction to make the cross-plate head 7 generate torque until the data collection system shows a peak torque, measure the peak torque, and calculate the peak undrained shear strength; continue to rotate in a clockwise direction for 6 turns, measure the final torque, and calculate the residual undrained shear strength. The ratio of the peak value to the residual undrained shear strength is the sensitivity of soft clay.

[0080] 2-4) After completing the depth measurement, shorten the retractable cross-plate probe rod 6, retract the cross-plate head 7 into the large-diameter short probe rod 1, and close the side cover 22 of the cross-plate shearing instrument.

[0081] 2-5) Repeat the above steps 2-2) to 2-4) to obtain the static penetration test results, undrained shear strength and sensitivity of soil at different depths.

[0082] 2-6) After the test is completed, the static sounding probe rod 21, the large-diameter short probe rod 1, the buckle probe rod 2 and the static sounding probe head 4 are pulled out together to end the entire test.

[0083] 3) Conduct static penetration test and drilling sampling at the same time, the steps are as follows:

[0084] 3-1) Carry out static penetration test in the same manner as in steps 1-1) and 1-2);

[0085] 3-2) The static penetration probe rod 21 is penetrated into the soil at a speed of 2 cm / s by the penetration equipment. When the specified depth is reached, the penetration is stopped and drilling sampling is carried out.

[0086] 3-3) Pull out the short probe rod 1 with large diameter and the probe rod with buckle 2 upwards. At this time, the sampler 3 remains stationary due to the friction force of the surrounding soil.

[0087] 3-4) When the spring lock bevel 16 contacts the probe rod buckle bevel 10, the probe rod buckle 9 will horizontally push the lock head 18 and compress the spring 19, and the probe rod buckle 9 gradually enters the sampler buckle 15. When the probe rod buckle 9 completely enters the sampler buckle 15, the spring lock hole 11 and the lock head 18 have the same height, the lock head 18 enters the spring lock hole 11, and the reserved gap 12 is completely fitted with the inner wall 17 of the sampler buckle. The probe rod buckle 9 is completely fitted with the gap in the sampler buckle 15. At this time, the probe rod buckle 9 and the sampler buckle 15 are completely locked.

[0088] 3-5) Insert the probe rod 2 with the buckle downward again, and the sampler 3 will be inserted downward into the soil body, and the soil sample will gradually enter the sampler 3. When the soil sample enters the sampler 3, the enclosed space in the sampler 3 will be reduced and the air pressure will increase. The air vent 20 is a funnel-shaped membrane made of rubber. When the air pressure inside is high, it will swell and open, allowing the gas to flow out, thus avoiding the generation of high air pressure in the sampler and making it difficult for the soil sample to enter the sampler 3.

[0089] 3-6) After the soil has completely entered the sampler 3, the static penetration probe rod 21, the large-diameter short probe rod 1, the probe rod with a buckle 2 and the sampler 3 are pulled out upwards together.

[0090] 3-7) When the sampler 3 moves upward, the soil sample tends to move downward, which will cause the enclosed space in the sampler to increase. The air vent 20 is constructed of a funnel-shaped membrane made of rubber. When the outside air pressure is high, it will shrink to close the opening, preventing the external soil sample and air from entering the sampling tube, thereby forming a negative pressure in the sampler 3.

[0091] 3-8) Under the action of friction and negative pressure between the soil sample and the inner wall of the sampler, the soil sample moves upward along with the sampler 3, thereby completing the sampling of the original soil. The total length of the sampler is about 1.3m, and the length of the static penetration probe is about 0.3m, so an original soil sample of about 1m in length can be obtained.

[0092] 3-9) After sampling is completed, unscrew the screw 24 and remove the detachable ring 23 from the sampler 3, thereby unlocking the probe rod buckle 9 and the sampler buckle 15.

[0093] 3-10) Repeat the above steps 3-1) to 3-9) to obtain the static penetration test results of soil at different depths, and obtain the original soil samples of soil at different depths.

[0094] 4) Conduct static penetration test, cross plate shear test and drilling sampling at the same time, such as Fig.15 As shown, the steps are as follows:

[0095] 4-1) Carry out static penetration test in the same manner as in steps 1-1) and 1-2);

[0096] 4-2) The static penetration probe 21 is penetrated into the soil at a speed of 2 cm / s by the penetration equipment. The penetration is stopped after reaching the specified depth. According to the above steps 2-2) to 2-5), the peak value and residual undrained shear strength of the soil at this depth are measured, and the sensitivity of the soil at this depth is calculated.

[0097] 4-3) Continue to penetrate downward to carry out static penetration test, and after reaching the next depth, carry out cross-plate shear test again to determine the sensitivity of soft clay at that depth.

[0098] 4-4) After reaching the sampling depth, stop penetrating and pull out the large-diameter short probe rod 1 and the probe rod with a buckle 2 upward. At this time, the sampler 3 remains stationary due to the friction force of the surrounding soil.

[0099] 4-5) When the probe rod buckle 9 of the buckled probe rod 2 moves upward to the position of the sampler buckle 15, the probe rod buckle 9 and the sampler buckle 15 are locked.

[0100] 4-6) The probe rod 2 with the buckle is penetrated downwards again, and the sampler 3 is penetrated downwards into the soil body together, and the soil sample gradually enters the sampler 3. The air vents 20 allow the gas to flow out, and a higher air pressure is never avoided in the sampler 3.

[0101] 4-7) After the soil has completely entered the sampler 3, the static penetration probe rod 21, the large-diameter short probe rod 1, the probe rod with a buckle 2 and the sampler 3 are pulled out upwards together.

[0102] 4-8) Under the action of the friction between the soil sample and the inner wall of the sampler and the negative pressure in the sampler, the soil sample moves upward along with the sampler 3, thereby completing the sampling of the original soil.

[0103] 4-9) Repeat the above steps 4-1) to 4-8) to obtain the static penetration test results, sensitivity and undisturbed soil samples of soil at different depths.

[0104] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many improvements and modifications without departing from the purpose of the present invention, such as changing the structure of the locking device between the sampler and the probe rod, changing the layout position and method of the cross-plate shear instrument, etc., all of which are protected by the present invention.

Claims

1. A static penetration test device for simultaneously sampling and measuring the sensitivity of soft clay, the test device comprising a probe rod and a sampler, characterized in that: The probe rod comprises a static penetration probe rod (21), a large-diameter short probe rod (1), a middle-length probe rod (2) and a static penetration probe head (4) which are coaxially connected from top to bottom; the outer diameter of the large-diameter short probe rod (1) is consistent with the outer diameter of the sampler (3), and the outer diameter of the sampler (3) is larger than the diameter of the static penetration probe head (4); The large-diameter short probe rod (1) is provided with a radial groove for installing a cross-plate shearing instrument, a retractable cross-plate probe rod (6) of the cross-plate shearing instrument is provided in the radial groove (71), a cross-plate head (7) is provided at the head of the retractable cross-plate probe rod (6), a cross-plate shearing instrument side cover (22) is provided at the notch of the radial groove (71), and a side cover shallow groove (72) is provided at the upper end of the notch; The middle long probe rod (2) comprises a rod body and a probe rod buckle (9) arranged at the lower end of the rod body, the probe rod buckle (9) is a cylindrical structure connected to the bottom periphery of the rod body and coaxial, the top inner edge of the cylindrical structure is provided with a buckle inclined surface (10), and the middle part of the cylinder is provided with a spring lock hole (11); The sampler (3) comprises a barrel and a sampler buckle (15) arranged at the inner opening of the top and matched with the probe buckle (9); the barrel is provided with an air vent (20); the axial dimension of the inner wall (17) of the sampler buckle (15) is consistent with the cylinder depth of the probe buckle (9); the thickness of the inner wall (17) of the sampler buckle is consistent with the reserved gap (12) between the cylinder of the probe buckle (9) and the rod body; a pair of spring lock mounting grooves are provided on the outer wall of the sampler buckle (15); the sampler The body of the spring lock (3) is provided with an annular groove corresponding to the axial position of the spring lock installation groove, and the annular groove is provided with a spring lock installation hole aligned with the position of the spring lock installation groove. After the spring lock installation groove and the spring lock installation hole are aligned, a spring lock (14) is installed therein; a detachable ring (23) is provided in the annular groove, and the inner surface of the detachable ring (23) is provided with a boss (235) aligned with the position of the spring lock installation groove. After the detachable ring (23) is installed, the boss (23) abuts against the spring lock (14); The probe rod is provided with a cable channel that passes through the static contact probe rod (21), the large-diameter short probe rod (1) and the middle-length probe rod (2); the cable and data line of the static contact probe (21) are led out from the cable channel; the rear wall of the radial slot (71) is provided with a through hole (61) that passes through the cable channel (5); the cable and data line of the retractable cross-plate probe rod (6) of the cross-plate shear instrument are led out from the cable channel (5) after passing through the through hole (61) on the rear wall of the radial slot.

2. The static penetration test device for simultaneous sampling and determination of sensitivity of soft clay according to claim 1, characterized in that: The spring lock (14) comprises a lock head (18), a spring (19) is arranged inside the lock head (18), a spring lock inclined surface (16) is arranged on the lower end surface of the lock head (18), and the spring lock inclined surface (16) is consistent with the buckle inclined surface (10) of the probe rod buckle (9).

3. The static penetration test device for simultaneous sampling and determination of sensitivity of soft clay according to claim 1, characterized in that: The upper and lower ends of the large-diameter short probe rod (1) are respectively connected to the static penetration probe rod (21) and the middle long probe rod (2) by welding, and the static penetration probe head (4) is connected to the middle long probe rod (2) by threading.

4. The static penetration test device for simultaneous sampling and determination of sensitivity of soft clay according to claim 1, characterized in that: The bottom surface of the large-diameter short probe rod (1) is the sampler load-bearing surface (8), the top surface of the sampler (3) is the sampler load-bearing surface (13), and there is a clearance fit between the inner wall of the barrel of the sampler (3) and the outer wall of the rod body of the middle long probe rod (2); when assembling the sampler (3), the sampler load-bearing surface (13) is pressed against the sampler load-bearing surface (8).

5. The static penetration test device for simultaneous sampling and determination of sensitivity of soft clay according to claim 1, characterized in that: The detachable circular ring (23) is composed of two semicircular rings that are embraced, and the two semicircular rings are respectively denoted as semicircular ring A (231) and semicircular ring B (232). A screw (233) is preset on the open end surface of the semicircular ring A (231), and a threaded hole (234) coaxial with the screw (233) is provided on the open end surface of the semicircular ring B (232). When installing the detachable circular ring (23), the bosses (235) on the inner surfaces of the semicircular ring A (231) and the semicircular ring B (232) are aligned with the spring lock (14), and then the screw (233) is screwed into the threaded hole (234) opposite to the semicircular ring A (231).

6. The static penetration test device for simultaneous sampling and determination of sensitivity of soft clay according to claim 1, characterized in that: The number of the air holes (20) arranged on the body of the sampler (3) is four and is evenly distributed along the same circumference. The air holes (20) are funnel-shaped membranes made of rubber.

7. A static penetration test method for simultaneously sampling and determining the sensitivity of soft clay, characterized in that: Using the test device as claimed in any one of claims 1 to 6, the cable and the data line are connected to the monitoring device, and wherein: 1) Static penetration test: The probe rod is penetrated into the soil at a speed of 2 cm / s through the penetration equipment to measure the cone tip resistance, side wall friction resistance and pore water pressure of the soil at different depths; 2) Cross plate shear test: Move the probe rod upward, open the side cover (22) of the cross-plate shear instrument, extend the retractable cross-plate probe rod (6), and extend the cross-plate head (7) a certain distance in the horizontal direction; rotate the probe rod clockwise to make the cross-plate head (7) generate torque until the torque data collection system shows a peak torque, measure the peak torque, and calculate the peak undrained shear strength; continue to rotate the probe rod clockwise for 6 circles, measure the final torque, and calculate the residual undrained shear strength; the ratio of the peak value to the residual undrained shear strength is the sensitivity of the soft clay; after the measurement is completed, shorten the retractable cross-plate probe rod (6), retract the cross-plate head (7) into the large-diameter short probe rod (1), and close the side cover (22) of the cross-plate shear instrument; 3) Drilling sampling: After the moving probe reaches the sampling depth, the penetration is stopped and the probe is pulled out upwards. At this time, the sampler (3) remains stationary under the action of the friction force of the surrounding soil. When the probe buckle (9) of the probe moves upwards to the position of the sampler buckle (15), the locking of the probe and the sampler is completed. The probe is penetrated downwards again, carrying the sampler (3) downwards into the soil, and the soil sample gradually enters the sampler (3). After the soil has completely entered the sampler (3), the probe is moved upwards and pulled out upwards together with the sampler (3). Under the action of the friction force between the soil sample and the inner wall of the sampler and the negative pressure in the sampler, the soil sample moves upwards along with the sampler (3), thereby completing the sampling of the original soil.

8. The test method according to claim 7, characterized in that: In the static penetration test, the large-diameter short probe rod (1) plays a role in expanding the hole and reducing the penetration force.

9. The test method according to claim 7, characterized in that: During the drilling sampling, the air vents (20) on the sampler (3) allow the gas in the sampler (3) to flow out, thereby preventing a high air pressure from being generated in the sampler (3).

10. The test method according to claim 7, characterized in that: The combination of projects to complete the test is one of the following: 1) Static penetration test; 1) static penetration test and 2) cross plate shear test; 1) static penetration test and 3) drilling sampling; 1) Static penetration test and 2) cross plate shear test and 3) drilling sampling.

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