WO2021000342A1

WO2021000342A1 - Apparatus for continuously measuring soil parameters of large-scale soft soil site

Info

Publication number: WO2021000342A1
Application number: PCT/CN2019/096254
Authority: WO
Inventors: 于龙; 韩云瑞; 杨庆
Original assignee: 大连理工大学
Priority date: 2019-07-01
Filing date: 2019-07-17
Publication date: 2021-01-07
Also published as: CN110346536A

Abstract

Provided is an apparatus for continuously measuring the soil parameters of a large-scale soft soil site, comprising three parts: a dragging structure main body I, a soil parameter measurement system II, and a dragging system III. The apparatus overcomes the limitation of a conventional single-point vertical measurement apparatus being unable to obtain continuous soil parameters in the direction of the rock stratum; by means of a single drag test, lateral long-distance continuous field measurement of soil strength, strain softening, and friction at the interface between soil and structure can be performed; the measured parameters can be used for guiding the design and construction of breakwater projects, submarine oil and gas pipelines, electrical cables, and optical cables. Particularly with the increasing development of deep-sea oil and gas resources, relying on the described method to measure the parameters of submarine soil and applying them to the design and stability evaluation of submarine pipelines, submarine electrical cables, and other engineering facilities is of great importance.

Description

Device for continuously measuring soil parameters of large-scale soft soil ground

Technical field

The invention belongs to the research technology fields of geotechnical, geology and environment, and relates to a continuous measurement device for soil parameters of a large-scale soft soil site. The device is particularly suitable for the design of underwater pipelines and the investigation of soil parameters before construction.

Background technique

Accurate measurement of soil parameters is the basis of all projects. As a kind of poor soil, soft soil generally has the characteristics of high natural water content, large natural void ratio, high compressibility, low shear strength, small consolidation coefficient, long consolidation time, high sensitivity, and poor water permeability. Therefore, the design and construction of soft soil sites are relatively risky. In engineering practice, realizing accurate measurement of soil parameters on soft soil sites is an important way to reduce engineering risks and optimize engineering design, and achieving rapid, continuous, and accurate measurement is not only an important test for experimental devices, but also an important test in engineering circles. The main problem faced.

The acquisition of traditional soil parameters is mainly to obtain core samples through on-site gravity sampling or borehole sampling, and then complete the measurement of soil related parameters through indoor tests. However, this method is difficult to accurately estimate the soil parameters of the actual site due to the disturbance of the soil during the sampling process and the limitations of the indoor test method itself, which will inevitably cause adverse effects on the project, and even affect the safety of the project. In recent years, on-site in-situ test equipment has been developed rapidly, static cone penetration test (CPT, CPTU), in-situ T-bar test, in-situ Ball-bar test, etc. have been widely used, and the test accuracy has also been significant Upgrade, especially for soft soil sites, these experimental devices have demonstrated unparalleled superiority. However, these experimental devices are all aimed at a certain target point to obtain soil parameters through vertical single penetration or circular penetration of the measuring equipment, which has good applicability for the measurement of soil parameters at a single target point. For large-scale and long-distance sites, the measurement results of this type of test device cannot reflect the changes in soil parameters along the stratum direction. By setting more vertical drilling points, the change relationship of soil parameters along the stratum direction can be obtained to a certain extent. However, the increase in engineering cost and time-consuming caused by this makes this kind of scheme in actual engineering also impossible. Realistic. Combining with the problems encountered in the current engineering, it is urgent to find an experimental device that can realize long-distance continuous measurement of soil parameters along the stratum direction. This device is of great significance to the design and stability evaluation of engineering built on soft soil.

Summary of the invention

Aiming at the problem that the existing experimental device cannot realize long-distance measurement of soil parameters along the stratum direction, the present invention proposes a device that can realize continuous measurement of soil parameters along the stratum direction. The device can be applied to the lateral continuous measurement of the soil parameters of the weak soil layers at the bottom of lakes, swamps, rivers, oceans, etc., and ultimately serve for breakwaters, submarine oil and gas pipelines, cables, optical cables, etc. relying on the horizontal long distance shallow soil parameters Design and construction engineering. Especially with the increasing development of deep-sea oil and gas resources, it is extremely important to measure the parameters of the submarine soil body based on the device provided by the present invention and apply it to the design and stability evaluation of submarine pipelines, submarine cables and other engineering facilities.

The technical scheme of the present invention:

A device for continuous measurement of soil parameters in a large-scale soft soil site, including three parts: drag structure main body I, soil parameter measurement system II and drag system III;

The bottom of the towing structure main body I is provided with a groove for installing the friction plate, and the upper part of the towing structure main body I is provided with a space for placing the counterweight lead block; the two ends of the towing structure main body I are equipped with support devices, by adjusting the angle of the support device and the upper counterweight Make the drag structure main body I sink into the soil to a certain depth;

The soil parameter measurement system II includes a soil strength measurement device, a soil strain softening relationship measurement device, a friction plate, a tension and compression sensor and an installation support; the soil strength measurement device is fixed to the front end of the towing structure body I through the installation support, and The installation direction points to the direction of movement; the soil strain softening relationship measurement device is fixed to the bottom of the towing structure body I through the mounting support, and its installation direction points to the direction of movement; the friction plate is fixed in the groove at the bottom of the towing structure body I through the tension and compression sensor. Ensure that it is level with the bottom of the towing structure body I;

The towing system III includes a towing boat, a towing cable terminal device and a towing cable; one end of the towing cable is connected to the front end of the towing structure main body I, and the other end is connected to the towing cable terminal device to drag the device to the soil layer The towing cable terminal equipment covers the cable retractable winch and the measurement signal acquisition system for the staff to analyze the measurement data from time to time; the towing boat should have a stable power system and try to ensure the test It advances at a uniform speed.

The soil strength measuring device is a T-bar penetrometer, a Ball-bar penetrometer or a static cone penetrometer.

The soil strain softening relationship measuring device is a T-bar penetrometer or a Ball-bar penetrometer.

One side and top surface of the friction plate are respectively connected with the transverse and normal tension and compression sensors, and the other side surface is a free end.

The above-mentioned device can not only obtain parameters such as soil strength, strain softening, and friction between soil and structure, but also the data obtained by the matching sensors in the embodiment can also be used for other parameters such as over-consolidation ratio, sensitivity, sand Determination of relative density, internal friction angle, soil compression modulus, deformation modulus, undrained modulus of saturated clay, foundation bearing capacity, single pile bearing capacity and sand liquefaction discrimination.

The beneficial effects of the present invention:

1) The device provided by the present invention breaks through the limitation that the traditional single-point vertical measurement device cannot obtain continuous soil strength parameters along the stratum direction, improves engineering safety and reduces the time cost and economic cost required in actual engineering measurement. Through the lateral arrangement of the CPT probe 7 and its lateral movement in the soil layer, the soil strength parameters within the drag distance can be continuously acquired.

2) Applying the device of the present invention, through the lateral arrangement of multiple T-bar probes 9 and making them move laterally in the soil layer, the on-site measurement of strain softening parameters can be completed after a drag test, and the analysis of seabed structure and seabed Slope stability has important reference value.

3) The interface friction parameters between soil and structure have always been the focus and difficulty of marine engineering design and stability analysis. The device provided by the present invention can be used to measure the interface friction parameters between soil and structure through a drag test. . At the same time, through the horizontal linear arrangement of multiple friction plates 12, the friction parameters and attenuation laws of the soil under different disturbance degrees can be obtained, which provides a parameter basis for the study of the interaction between soil and structure in engineering practice.

4) According to the device of the present invention, the lateral long-distance continuous measurement of soil parameters can be realized, and the measured parameters can be used to guide the design and construction of breakwaters, submarine oil and gas pipelines, electrical cables, and optical cables. Especially with the increasing development of deep-sea oil and gas resources, it is of great significance to measure the parameters of the submarine soil body based on the device provided by the present invention and apply it to the design and stability evaluation of submarine pipelines, submarine cables and other engineering facilities.

Description of the drawings

Figure 1 is a schematic diagram of the proposed test device provided by an embodiment of the present invention.

Fig. 2 is a three-dimensional oblique view of a towing device provided by an embodiment of the present invention.

Fig. 3 is a side view of a towing device provided by an embodiment of the present invention.

Fig. 4 is a front view of a towing device provided by an embodiment of the present invention.

Fig. 5 is a layout diagram of the bottom device of the towing device provided by an embodiment of the present invention.

Fig. 6 is a layout diagram of a partial T-bar penetrometer at the bottom of a towing device provided by an embodiment of the present invention.

Fig. 7 is a schematic diagram of measuring a friction plate at a local position of the bottom end of a towing device according to an embodiment of the present invention.

FIG. 8 is a schematic diagram of the change of the strength of the soil body measured based on the CPT probe provided by the embodiment of the present invention.

Fig. 9(a) is a schematic diagram of resistance changes measured at different positions of the T-bar probe provided by an embodiment of the present invention.

Figure 9(b) is a schematic diagram of the resistance attenuation relationship measured based on a certain position of the T-bar probe provided by an embodiment of the present invention.

Fig. 10(a) is a schematic diagram of the change of the friction force measured based on the friction plate provided by the embodiment of the present invention.

Fig. 10(b) is a schematic diagram of vertical pressure changes measured based on the friction plate provided by an embodiment of the present invention.

Fig. 10(c) is a schematic diagram of the friction coefficient variation obtained based on the friction plate provided by the embodiment of the present invention.

Figure 11(a) is a schematic diagram of the attenuation relationship of shear stress obtained based on the friction plate provided by an embodiment of the present invention.

FIG. 11(b) is a schematic diagram of the attenuation relationship of the friction coefficient obtained based on the friction plate provided by the embodiment of the present invention.

In the figure: 1 towing structure top plate; 2 hollow ribs; 3 towing cable pull ring; 4 counterweight lead block; 5 towing roller; 6 fixing screws; 7 CPT probe; 8 CPT mounting support; 9 T-bar probe; 10 T-bar mounting support; 11 tension and compression sensor; 12 friction plate; 13 tugboat; 14 towline terminal equipment (including retractable winches and data acquisition equipment); 15 towline (with high tensile strength and capable of transmitting sensors) Acquire the Signal).

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described here are part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various configurations.

Therefore, the detailed description of the embodiments of the invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present invention.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

The positional relationship indicated by "up", "down", "left", "right", etc. in the description of the present invention is based on the position and position relationship shown in the drawings, or the position usually placed when the product of the invention is used Or positional relationship, or the position or positional relationship commonly understood by those skilled in the art, is only for the convenience of the description in this embodiment, and does not indicate or imply that the equipment and components referred to must have a specific orientation, and therefore cannot be understood as Restrictions on the invention.

In addition, the sequential terms such as "first", "second", ..., "tenth" appearing in the present invention are only for ease of description, and cannot be understood as indicating or implying relative importance.

Example 1

The towing structure main body I includes a towing structure top plate 1, a hollow rib 2, a towing cable pull ring 3, a counterweight lead block 4, a towing roller 5 and a fixing screw 6; the towing structure top plate 1 and the hollow rib 2 constitute a towing structure The outer frame of the main body I, the front end surface of the hollow rib 2 is an arc-shaped surface, and the bottom surface of the hollow rib 2 has multiple grooves, both of which are made of stainless steel; the upper part of the drag structure top plate 1 is provided with a hollow structure With the weighted lead block 4, cables can be arranged in the hollow rib 2; there are two drag rollers 5, which are arranged on both sides of the top plate 1 of the drag structure by fixing screws 6, and the drag rollers 5 can surround the fixing screws 6. Rotation occurs to control the penetration depth of the hollow rib 2; after the drag roller 5 is adjusted to a specified angle, the fixing screw 6 is tightened; the weight lead 4 is used to change the weight of the drag structure body I to ensure the drag structure body I sinks into the soil to a certain depth; the towing cable pull ring 3 is arranged at the front end of the top plate 1 of the towing structure to connect with the external towing system III, so that the towing structure main body I moves at a uniform speed in the soil;

The soil parameter measurement system II includes CPT probe 7, CPT mounting support 8, T-bar probe 9, T-bar mounting support 10, tension and compression sensor 11 and friction plate 12;

The CPT probe 7 is fixed to the front end of the hollow rib 2 through the CPT mounting support 8, and its installation direction points to the direction of movement; in the test, the voltage signal of the CPT probe 7 during the lateral movement is collected, and the measured voltage signal and intensity CPT The conversion relationship of the resistance of the probe 7 determines the resistance of the CPT probe 7; then through the relationship between the obtained resistance and the strength of the soil, the strength of the soil that changes continuously along the direction of movement is obtained;

The T-bar mounting support 10 is fixed on the bottom surface of the hollow rib 2 of the drag structure and arranged along the same line. It is used to fix the tension and compression sensor 11, and the tension and compression sensor 11 is connected with a T-bar probe 9, T- The bar probe 9 points to the direction of movement and ensures that the T-bar probe 9 is in the same straight line; the soil at the same position is disturbed by multiple T-bar probes 9 at the bottom of the drag device during the travel of the device; by measuring the T-bar The voltage measurement signal of the tension and compression sensor 11 connected to the probe 9 is obtained to obtain the resistance of the T-bar probe 9 during the travel; for the soil at the same position, the resistance of the T-bar probe 9 and the corresponding T- of the disturbed soil are obtained. The relationship between the 9 number of bar probes; combined with the relationship between the 9 number of disturbed soil T-bar probes and the cumulative plastic strain of the soil, then the relationship between resistance and cumulative plastic strain is obtained; combined with T-bar The relationship between the resistance of the probe 9 and the strength of the soil, and finally determine the relationship between the strength of the soil and the cumulative plastic strain, that is, the relationship between soil strain and softening;

The friction plate 12 is installed in the bottom groove of the hollow rib 2 and its lower surface is level with the bottom surface of the hollow rib 2; one side end surface and the upper surface of the friction plate 12 are arranged horizontally and vertically on the hollow ribs. The tension and compression sensor 11 in the groove at the bottom of the plate 2 is connected, and it is ensured that the end surface of the friction plate 12 not connected to the tension and compression sensor 11 is free; the towing device directly measures the voltage signal of the tension and compression sensor 11 when it is traveling in the soil. And through the transformation relationship between it and the force, the friction force and vertical pressure of the soil body on the friction plate 12 are obtained; for clay, the friction resistance of the soil body passing through the same position and the corresponding friction plate 12 that disturb the soil body are combined. The relationship between the number, and the relationship between the number of friction plates 12 of the disturbed soil and the relative displacement of the soil, and finally the relationship between the friction resistance of the friction plate 12 and the cumulative relative displacement; for sandy soil, Through the relationship between the frictional resistance of the friction plate 12 at the same position and the vertical pressure it receives, the friction coefficient between the friction plate 12 and the soil is obtained, combined with the number of friction plates 12 that disturb the soil at the same position and the soil The relationship between the relative displacements, and finally the relationship between the friction coefficient of the friction plate 12 and the cumulative relative displacement is obtained;

The towing system III includes a towboat 13, a towline terminal device 14 and a towline 15. One end of the towline 15 is connected to the towline pull ring 3, and the other end is connected to the towline terminal device 14 to tow the device Make it move in the soil layer and transmit the measurement signals of the CPT probe 7 and the sensor 11; the towline terminal device 14 covers the cable retractable winch and the measurement signal acquisition system of the CPT probe 7 and the tension and compression sensor 11 to work Personnel analyze the measurement data from time to time; the tugboat 13 should have a stable power system to ensure that it advances at a uniform speed during the test.

The material used between the adjacent friction plates 12 is the same as the material used for the friction plates 12, and the distance between the adjacent friction plates 12 is required to be the same as the length of the friction plates 12.

Example 2

This embodiment is a continuous measurement device for soil parameters of a large-scale soft soil site. The experimental device provided by this embodiment is simple and can realize continuous measurement of soil parameters along a long distance in the stratum direction, and can be used for underwater pipelines and cables. Design and construction of other structures.

Referring to Figs. 1 and 2, the experimental device for continuously measuring soft soil field parameters along the stratum direction provided by this embodiment can be completed by a lateral dragging device. The towing device includes towing structure top plate 1, hollow rib 2, towing cable pull ring 3, counterweight lead block 4, towing roller 5, fixing screw 6, CPT probe 7, CPT mounting support 8, T-bar probe 9, T -bar mounting support 10, tension and compression sensor 11 and friction plate 12; tension and compression sensor 11 is respectively connected with T-bar probe 9 and T-bar fixed support 10; CPT probe 7 is connected with its mounting support 8; friction plate 12 They are respectively connected with the tension and compression sensors 11 arranged horizontally and vertically.

With reference to the drawings and technical solutions, the main steps of this embodiment are as follows:

First, assemble the towing device

Referring to Figures 2 and 3, the towing structure roof 1 and the hollow ribs 2 are made of stainless steel. In the test, the counterweight 4 can be controlled to make the hollow ribs 2 sink into the soil to a certain depth. The tow cable pull ring 3 is installed at the front end of the top plate 1 of the towing structure, and is used to tow the towing device through the tow cable 15 in the test. Two CPT probes 7 are connected to the mounting support 8 and fixed on the front end of the hollow rib 2. The CPT probe 5 uses an international standard probe, that is, the top angle of the probe is 60°, and the bottom area is 10 cm ² .

3, 4 and 5, the T-bar support 10 is arranged at the bottom end of the hollow rib 2 of the towing device and 8 are arranged along the same straight line. The tension and compression sensor 11 is respectively connected to the T-bar support 10 and T-bar The probe 9 is connected and points to the moving direction of the towing device. The size of T-bar probe 9 is made of stainless steel cylinder with a diameter of 4cm and a length of 10cm.

Referring to Figure 3, Figure 4, Figure 5 and Figure 7, 15 friction plates 12 are evenly arranged longitudinally along the bottom end of the hollow rib 2 of the towing device, and 8 friction plates 12 are respectively corresponding to the horizontal and vertical tension and compression sensors 11 connection. Friction plates 12 of the same specification are installed adjacent to the friction plates 12 connected with the tension and compression sensors 11, and one end of the rubbing plates 12 is required to be free. The friction plate 12 has a length of 10 cm and a width of 5 cm.

Second, equipment performance testing and debugging

After the towing device is assembled, the CPT probe 7, the T-bar probe 9 and the friction plate 12 are pulled and pressed to verify the sensitivity and effectiveness of the sensor transmission signal, the streamer 15 and the acquisition equipment 14 and other supporting facilities. The terminal device 14 performs trial collection of data. After the equipment is tested without any problems, prepare for the next experiment.

Third, drop the towing device onto the surface of the soil layer to be tested

Lower the assembled towing device slowly on the surface of the soil through a gantry crane or other lifting equipment, and control the lowering speed during the lowering process to avoid damage to the equipment caused by large inertial forces. After the towing device is lowered to the designated position, continue to lower the towline 15 and make the tug 13 move forward at a low speed, and control the length of the towline 15 so that the angle between the towline 15 and the mud surface is sufficiently small (generally within 30°). After the towline 15 reaches the specified angle, check the operation of the towline terminal equipment 14. After the equipment is checked correctly, the data collection equipment is turned on.

Fourth, the horizontal drag of the drag device

After the test preparations are ready, the tug 13 is used to drag the towing device along the designated direction. During towing, the speed and direction of the tug 13 are strictly controlled to ensure that the tug 13 advances at a constant speed. The collected data is constantly observed, analyzed and saved.

Fifth, recycling of equipment

After the experiment is completed, the tugboat 13 slowly reverses and at the same time tightens the towline 15, lifts the towing device upwards, and returns to the deck of the tugboat 13 for equipment inspection and storage.

Sixth, the processing of measurement data

After a drag test is completed, the main soil parameters and data analysis process measured by the device of the present invention are as follows.

1) Determination of soil shear strength

As one of the important soil parameters, the shear strength of the soil is mainly determined based on the measurement results of the static cone penetration (CPT) probe 7. The calculation process of the soil strength is as follows:

Among them: Q _c is the cone tip resistance of the probe, N; A is the cone bottom area of the probe, m ² ; N _kt is the bearing capacity coefficient of the probe, which is between 11 and 19, and the general value is 15.0. According to the test device provided by the present invention and the above-mentioned strength calculation method, the relationship of the soil strength change after the test is shown in Fig. 8.

2) Determination of soil strain softening parameters

The calculation of the strain softening parameter is mainly based on the measurement data of the tension and compression sensor 11 corresponding to the T-bar probe 9 at different positions at the bottom of the hollow rib 2 of the towing device. The resistance change of the T-bar probe 9 during the dragging of the towing device As shown in Figure 9(a).

The strain softening model of the soil is:

Among them: s _u0 is the initial strength of the soil, in kPa; δ _rem is the reciprocal of the sensitivity (S _t ) of the soil; ξ ₉₅ is the cumulative plastic strain value corresponding to a 95% decrease in the strength of the soil.

The initial strength of the soil (s _u0 ) is determined by the measurement result of the first T-bar probe 9 in the movement direction of the bottom end of the hollow rib 2 of the towing device. The calculation process is as follows:

Among them: q _T-bar is the resistance of the T-bar probe 9 during lateral movement in the soil body; N _T-bar is the bearing capacity coefficient of the T-bar, which is between 9.14 and 11.94, and the general value is 10.5; D To select the diameter of the T-bar, m; L is the length of the T-head in the T-bar, m.

After the soil at the same location is disturbed by multiple T-bar probes 9, the resistance attenuation relationship is as follows:

Among them, n is the number of 9 T-bar probes passing at the same position along the direction of movement. Considering the average strain during the penetration process, the count generally starts from 0.25 and gradually accumulates with 0.5 according to the number of 9 T-bar probes, that is, n The value sequence is 0.25, 0.75, 1.25 for incremental changes; q _n is the resistance value of the n-th T-bar probe 9 that starts counting along the movement direction, and q _in is the T-bar probe 9 at the front end of the movement direction The resistance value of q _rem is the resistance value of the last T-bar probe 9 (the corresponding value when the resistance is stable, generally the measured resistance value of the last T-bar), and N ₉₅ is the corresponding value when the strength is reduced by 95% 9 T-bar probes. After the soil at a certain position is disturbed by the T-bar probe 9 of different times, the measured resistance attenuation is shown in Figure 9(b), and N ₉₅ can be obtained by analyzing the resistance attenuation relationship as shown in Figure 9(b).

The sensitivity of the soil (S _t ) can be estimated according to the following formula:

ξ ₉₅ can be calculated by the following formula,

ξ ₉₅ ＝2N ₉₅ ξ _T-bar

Where ξ _T-bar can be calculated according to the following formula,

ξ _T-bar =0.83log(S _t )+3.09

3) Determination of friction parameters at the interface between soil and structure

The interface friction coefficient between the soil and the structure is obtained by measuring the pressure and friction resistance of the friction plate 12 at the bottom end of the towing device. The steps for obtaining soil friction parameters are as follows:

3.1) Friction parameters of cohesive soil

Since the soil at the same location is affected by the friction of the multiple friction plates 12 at the bottom of the device during the dragging process along the stratum direction, and the disturbance of the soil by different friction plates 12 is different, the friction resistance of the friction plates 12 There will be significant differences. The frictional resistance of the friction plate 12 is obtained by the vertical tension and compression sensor 11. In the experiment, the friction force along the stratum direction is shown in Figure 10(a). The shear stress of the m-th friction plate 12 at the same position in the soil body is

Where: F _f,m is the friction force experienced by the m-th friction plate 12 at the analysis position, N; W is the width of a single friction plate 12, in m; L is the length of a single friction plate 12, in m.

After the friction of m friction plates 12, the friction displacement of the soil is

S _(m) = mL

Through the above calculation, the attenuation law of the interface friction parameter (shear stress) between the soil and the structure of the cohesive soil material can be obtained, as shown in Figure 11(a).

3.2) Friction parameters of sandy soil

The friction coefficient between the soil and the structure is obtained by measuring the pressure and friction resistance of the friction plate 12 at the bottom of the towing device. During the towing process, the vertical pressure received by the friction plate 12 is measured by the vertical tension and compression sensor 11. In the test, the vertical pressure of the friction plate 12 changes as shown in Figure 10(b); The force is obtained according to the measurement results of the tension and compression sensors 11 arranged laterally. The friction force in the test is shown in Figure 10(a). According to the Coulomb friction criterion, the friction coefficient can be calculated by the following formula.

Among them: F _f is the lateral friction force received by the friction plate 12 during the towing process, N; F _N is the vertical pressure received by the friction plate 12 during the towing process, N. The change of the friction coefficient of the friction plate 12 at different positions during the towing process is shown in FIG. 10(c).

The coefficient of friction of the soil at the same location is

Among them: F _N,m is the vertical pressure of the m-th friction plate 12 at the analysis position, N; the attenuation relationship of the friction coefficient obtained after the test with the friction displacement is shown in Figure 11(b).

The above are only preferred examples of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the ideas and principles of the present invention should be included in the protection scope of the present invention.

Claims

A device for continuously measuring soil parameters of a large-range soft soil site, characterized in that the device for continuous measurement of soil parameters of a large-range soft soil site includes a drag structure main body I, a soil parameter measurement system II, and a drag system III. section;

The bottom of the towing structure main body I is provided with a groove for installing the friction plate, and the upper part of the towing structure main body I is provided with a space for placing the counterweight lead block; the two ends of the towing structure main body I are equipped with support devices, by adjusting the angle of the support device and the upper counterweight Make the drag structure main body I sink into the soil to a certain depth;

The soil parameter measurement system II includes a soil strength measurement device, a soil strain softening relationship measurement device, a friction plate, a tension and compression sensor and an installation support; the soil strength measurement device is fixed to the front end of the towing structure body I through the installation support, and The installation direction points to the direction of movement; the soil strain softening relationship measurement device is fixed to the bottom of the towing structure body I through the installation support, and its installation direction points to the direction of movement of the towing device; the friction plate and the tension and compression sensor fixed in the bottom groove of the towing structure body I Connected and level with the bottom of the drag structure main body I;

The towing system III includes a towing boat, a towing cable terminal device and a towing cable; one end of the towing cable is connected to the front end of the towing structure main body I, and the other end is connected to the towing cable terminal device to drag the device to the soil layer The towing cable terminal equipment covers the cable retractable winch and the measurement signal acquisition system for the staff to analyze the measurement data from time to time; the towing boat should have a stable power system and try to ensure the test Move at a uniform speed.
The continuous measurement device for soil parameters of a large-scale soft soil site according to claim 1, wherein the soil strength measurement device is a T-bar penetrometer, a Ball-bar penetrometer or a static cone penetration tester. instrument.
The continuous measurement device for soil parameters of a large-scale soft soil site according to claim 1 or 2, wherein the soil strain softening relationship measurement device is a T-bar penetrometer or a Ball-bar penetrometer.
The device for continuously measuring soil parameters of a large-scale soft soil site according to claim 1 or 2, wherein one side and top surface of the friction plate are respectively connected with transverse and normal tension and compression sensors, and the other One side surface is the free end.
The device for continuously measuring soil parameters of a large-scale soft soil site according to claim 3, wherein one side and the top surface of the friction plate are respectively connected with transverse and normal tension and compression sensors, and the other side For the free end.