阅读说明：本技术 一种地下工程冻结试验系统 (Underground engineering freezing test system ) 是由 张会芝 刘纪峰 陈孝国 杨悦 连跃宗 黄凌君 于 2019-10-29 设计创作，主要内容包括：本发明涉及一种地下工程冻结试验系统,包含底座、支撑于底座上试验箱、支撑于底座上的加固机构、以及施压装置；所述试验箱包含相邻的多个第一压板和多个相邻的第二压板,所述第一压板和第二压板围拢成一收纳腔室,所述收纳腔室能够填入试验土；还包含有冷冻装置,所述冷冻装置包含冷气输出机构、冷气管座、连通冷气输出机构和冷气管座的冷气导管组件、以及冷气置入管,所述冷气置入管一端联接在冷气管座上且另一端能够置入试验土中；所述试验土与所述试验箱构成为透明结构。(The invention relates to an underground engineering freezing test system which comprises a base, a test box supported on the base, a reinforcing mechanism supported on the base and a pressure applying device, wherein the reinforcing mechanism is arranged on the base; the test box comprises a plurality of adjacent first pressing plates and a plurality of adjacent second pressing plates, the first pressing plates and the second pressing plates are enclosed to form a containing chamber, and test soil can be filled into the containing chamber; the device comprises a cold air output mechanism, a cold air pipe seat, a cold air pipe component communicated with the cold air output mechanism and the cold air pipe seat, and a cold air imbedding pipe, wherein one end of the cold air imbedding pipe is connected to the cold air pipe seat, and the other end of the cold air imbedding pipe can be embedded into test soil; the test soil and the test box are formed into a transparent structure.)

1. A freezing test system for underground engineering comprises a base, a test box supported on the base, a reinforcing mechanism supported on the base and a pressure applying device; the test box comprises a plurality of adjacent first pressing plates and a plurality of adjacent second pressing plates, the first pressing plates and the second pressing plates are enclosed to form a containing chamber, and test soil can be filled into the containing chamber; the device is characterized by also comprising a refrigerating device, wherein the refrigerating device comprises a cold air output mechanism, a cold air pipe seat, a cold air pipe component for communicating the cold air output mechanism and the cold air pipe seat, and a cold air imbedding pipe, one end of the cold air imbedding pipe is connected to the cold air pipe seat, and the other end of the cold air imbedding pipe can be embedded into test soil; the test soil and the test box are formed into a transparent structure.

2. The underground engineering freeze test system of claim 1, wherein the reinforcement mechanism comprises:

the first frame is supported on the base and comprises a plurality of first supporting columns, and the first supporting columns are enclosed in a mode that the length direction of the first supporting columns extends in a direction parallel to the vertical direction or orthogonal to the vertical direction so as to be supported on the outer peripheral side of the test box; and

the second frame is supported on the base and comprises a plurality of second supporting columns; the second supporting columns are enclosed in a mode that the length direction of the second supporting columns extends parallel to the vertical direction or the other side orthogonal to the vertical direction so as to be supported on the outer peripheral side of the first frame;

the second pressing plate is fixedly supported on the inner peripheral side of the first frame, and the first pressing plate can apply pressure to the test soil in the containing chamber along the lateral direction under the pushing of the pressing device.

3. The underground engineering freeze test system of claim 2, comprising a water injection means and a water drainage means; the drainage device is provided with a drainage port which is arranged at the lower side of the test soil and is used for downwards draining seepage water; the water injection device is communicated with a water source and comprises a plurality of water outlets, and the water outlets are arranged at intervals along the vertical direction to inject water into the test soil at different depths so as to change the humidity of the test soil at different depths.

4. The system of claim 3, wherein the test chamber comprises two adjacent first platens and two adjacent second platens, the first and second platens configured in a quadrilateral configuration when viewed vertically.

5. The underground engineering freeze test system of claim 4, comprising an upper bracket and a vertical pressure loading mechanism supported on the upper bracket, wherein the pressure applying device comprises a first lateral pressure loading mechanism for pushing one second pressure plate to move and a second lateral pressure loading mechanism for pushing the other second pressure plate to move.

6. The underground engineering freeze test system of claim 2, wherein the cold gas insertion tube is configured as a copper tube or a plastic hose.

7. The system of claim 2, wherein the first frame, the first platen and the second platen have a height in a vertical direction that is less than a height of the second frame, the cold air duct is supported by the second frame, and the cold air duct assembly can extend from an upper side of the first platen and/or the second platen into the receiving chamber and into the test soil.

8. The underground engineering freezing test system according to any one of claims 1 to 7, comprising a light source device, a shooting device and a data acquisition device; the test box and the test soil are of a transparent structure, the light source device comprises a laser source and a filter, the filter converts light of the laser source into a surface light source and projects the surface light source onto the test soil, the shooting device is used for displacement change inside the test soil when the freezing device freezes the test soil through the cold air inserting tube, and the data acquisition device comprises a displacement sensor, a pressure sensor and an osmometer which are arranged inside the test soil; and the displacement sensor, the pressure sensor, the osmometer and the shooting device are respectively connected with a computer through electric signals.

9. A subterranean project freeze test system according to claim 8, wherein the test system is capable of performing the following steps:

filling test soil into the test box;

acquiring water seepage pressure data of test soil through a osmometer, and freezing the test soil through a refrigerating device when the water seepage pressure data reaches a preset water seepage pressure threshold value, wherein the refrigerating device comprises a plurality of cold air imbedding pipes communicated with cold air pipe seats, cold air outlets of the cold air imbedding pipes are arranged at different positions of the test soil, and the cold air imbedding pipes are sequentially opened to freeze the different positions of the test soil according to different sequences;

acquiring displacement data of the test soil and pressure data inside the test soil at different positions through the displacement sensor and the pressure sensor, and transmitting the displacement data and the pressure data to a computer through electric signals for data analysis;

acquiring a displacement change image of the test soil through a camera device, and transmitting the image to a computer through an electric signal for image analysis;

and analyzing the displacement data, the pressure data, the water seepage pressure data and the image of the test soil through a computer.

Technical Field

The invention belongs to the field of geotechnical engineering model tests, and particularly relates to an underground engineering freezing test system.

Background

With the continuous promotion of the urbanization construction process in China, large deep foundation pit engineering is frequently used, and the complexity, the design and the construction difficulty of the large deep foundation pit engineering become more and more challenging. The foundation pit engineering has the remarkable new characteristics of depth, large size, near and difficult, the research of the foundation pit engineering also widely relates to the mechanical fields of geotechnical engineering, structural engineering, seepage, vibration and the like, and the influence of the seepage and traffic load on the foundation pit engineering is more and more concerned.

One of the methods currently used in underground construction is freezing, which uses artificial refrigeration technology to freeze water in the formation and transform the underground rock and soil into frozen earth. However, the conditions of the underground rock soil in different regions and different climates are different, so that the stability and the strength of the frozen underground rock soil are changed. Therefore, tests for the effects of different environments on freezing effects are necessary. Based on this, the inventors have proposed the present application.

Disclosure of Invention

The invention aims to provide an underground engineering freezing test system which is provided with a test box filled with test soil and a freezing device, wherein the test soil and the test box are arranged into transparent structures, so that the aim of observing the change of the test soil in the process of freezing the test soil by the freezing device is fulfilled.

The invention provides an underground engineering freezing test system which comprises a base, a test box supported on the base, a reinforcing mechanism supported on the base and a pressure applying device, wherein the reinforcing mechanism is arranged on the base; the test box comprises a plurality of adjacent first pressing plates and a plurality of adjacent second pressing plates, the first pressing plates and the second pressing plates are enclosed to form a containing chamber, and test soil can be filled into the containing chamber; the device is characterized by also comprising a refrigerating device, wherein the refrigerating device comprises a cold air output mechanism, a cold air pipe seat, a cold air pipe component for communicating the cold air output mechanism and the cold air pipe seat, and a cold air imbedding pipe, one end of the cold air imbedding pipe is connected to the cold air pipe seat, and the other end of the cold air imbedding pipe can be embedded into test soil; the test soil and the test box are formed into a transparent structure.

Preferably, the reinforcing mechanism includes: the first frame is supported on the base and comprises a plurality of first supporting columns, and the first supporting columns are enclosed in a mode that the length direction of the first supporting columns extends in a direction parallel to the vertical direction or orthogonal to the vertical direction so as to be supported on the outer peripheral side of the test box; the second frame is supported on the base and comprises a plurality of second supporting columns; the second supporting columns are enclosed in a mode that the length direction of the second supporting columns extends parallel to the vertical direction or the other side orthogonal to the vertical direction so as to be supported on the outer peripheral side of the first frame; the second pressing plate is fixedly supported on the inner peripheral side of the first frame, and the first pressing plate can apply pressure to the test soil in the containing chamber along the lateral direction under the pushing of the pressing device.

Preferably, the underground engineering freezing test system comprises a water injection device and a water drainage device; the drainage device is provided with a drainage port which is arranged at the lower side of the test soil and is used for downwards draining seepage water; the water injection device is communicated with a water source and comprises a plurality of water outlets, and the water outlets are arranged at intervals along the vertical direction to inject water into the test soil at different depths so as to change the humidity of the test soil at different depths.

Preferably, the test chamber comprises two adjacent first press plates and two adjacent second press plates, and the first press plates and the second press plates are in a quadrilateral structure when viewed in the vertical direction.

Preferably, the underground engineering freezing test system further comprises an upper bracket and a vertical pressure loading mechanism supported on the upper bracket, and the pressure applying device comprises a first lateral pressure loading mechanism for pushing one second pressure plate to move and a second lateral pressure loading mechanism for pushing the other second pressure plate to move.

Preferably, the cold air introducing pipe is formed as a copper pipe or a plastic hose.

Preferably, the height of the first frame, the first pressing plate and the second pressing plate in the vertical direction is smaller than that of the second frame, the cold air pipe seat is supported on the second frame, and the cold air pipe assembly can extend into the containing chamber from the upper side of the first pressing plate and/or the second pressing plate and is placed into the test soil.

Preferably, the underground engineering freezing test system further comprises a light source device, a shooting device and a data acquisition device; the test box and the test soil are of a transparent structure, the light source device comprises a laser source and a filter, the filter converts light of the laser source into a surface light source and projects the surface light source onto the test soil, the shooting device is used for displacement change inside the test soil when the freezing device freezes the test soil through the cold air inserting tube, and the data acquisition device comprises a displacement sensor, a pressure sensor and an osmometer which are arranged inside the test soil; and the displacement sensor, the pressure sensor, the osmometer and the shooting device are respectively connected with a computer through electric signals.

In a second aspect, the present invention provides an underground engineering freezing test system, which can be executed with the following steps:

filling test soil into the test box;

acquiring water seepage pressure data of test soil through a osmometer, and freezing the test soil through a refrigerating device when the water seepage pressure data reaches a preset water seepage pressure threshold value, wherein the refrigerating device comprises a plurality of cold air imbedding pipes communicated with cold air pipe seats, cold air outlets of the cold air imbedding pipes are arranged at different positions of the test soil, and the cold air imbedding pipes are sequentially opened to freeze the different positions of the test soil according to different sequences;

acquiring displacement data of the test soil and pressure data inside the test soil at different positions through the displacement sensor and the pressure sensor, and transmitting the displacement data and the pressure data to a computer through electric signals for data analysis;

acquiring a displacement change image of the test soil through a camera device, and transmitting the image to a computer through an electric signal for image analysis;

and analyzing the displacement data, the pressure data, the water seepage pressure data and the image of the test soil through a computer.

By adopting the technical scheme, the invention can obtain the following technical effects.

1. The invention provides an underground engineering freezing test system which is provided with a test box filled with test soil and a freezing device, wherein the test soil and the test box are arranged into transparent structures, so that the aim of observing the change of the test soil in the process of freezing the test soil by the freezing device is fulfilled.

Drawings

Fig. 1 and 2 depict schematic views of the underground engineering freeze test system of the present invention viewed from adjacent sides upward.

Fig. 3 depicts a schematic view of the underground engineering freeze test system of the present invention from the top side.

Figures 4 and 5 depict a schematic view of the ripping mechanism of the present invention viewed from different directions.

Figure 6 depicts a schematic view of the test chamber, base and reinforcing mechanism of the present invention viewed from the upper side (i.e., vertically from top to bottom).

Fig. 7 depicts a schematic view of the upper bracket of the present invention viewed from the upper side.

Fig. 8 depicts a schematic view of the upper brace of the present invention viewed from the side up.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "upper", "lower", "upper section", "lower section", "upper side", "lower side", "middle", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate orientations and positional relationships indicated based on the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

The structure and function of the solution of the present application will now be described in detail with reference to fig. 1 to 8.

The invention provides an underground engineering freezing test system, which comprises a base 2, a test box 1 supported on the base 2, a reinforcing mechanism supported on the base 2, a pressure applying device and a refrigerating device C, and is shown in figures 1 and 2. The test box 1 comprises a plurality of adjacent first pressing plates 11 and a plurality of adjacent second pressing plates 12, the first pressing plates 11 and the second pressing plates 12 are enclosed to form a containing chamber 13, and the containing chamber 13 can be filled with test soil. The test soil testing device comprises a test soil, a cold air pipe seat, a cold air pipe assembly and a cold air imbedding pipe, wherein the test soil is filled in the test soil, the cold air pipe assembly is communicated with the cold air pipe seat, and the cold air imbedding pipe is connected with the cold air pipe seat. The test soil and the test chamber 1 are formed into a transparent structure. Preferably, the cold air inlet pipe is formed as a copper pipe or a plastic hose.

With reference to fig. 6 and 7, the reinforcing mechanism includes a first frame 3 and a second frame supported on the base 2, the first frame 3 includes a plurality of first support columns 31, and the first support columns 31 are enclosed in such a manner that the longitudinal direction extends in parallel to the vertical direction or in a direction orthogonal to the vertical direction, so as to be supported on the outer peripheral side of the test chamber 1. The second frame includes a plurality of second support columns 4, and the second support columns 4 are enclosed so that the longitudinal direction thereof extends in parallel to the vertical direction or orthogonal to the vertical direction, and are supported on the outer peripheral side of the first frame 3. The second pressing plate 12 is fixedly supported on the inner peripheral side of the first frame 3, and the first pressing plate 11 can apply pressure to the test soil in the accommodating chamber 13 along the lateral direction under the pushing of the pressing device.

First frame 3 contains four reinforced walls, observes from top to bottom, four reinforced wall constitutes for tetragonal structure at the ascending cross-section of vertical direction, and each reinforced wall includes along vertical two liang of looks butt and the rigid coupling first support column 31 together, and first support column 31 comprises the channel-section steel, and wherein, two adjacent first support columns 31 pass through fasteners such as screw or bolt by the lateral wall of channel-section steel and realize fastening connection. The two adjacent reinforcing walls are fixedly connected with each other through a right-angle connecting piece 55. Specifically, along the circumferential direction, two adjacent first support columns 31 are fixedly connected through a right-angle connecting piece 55 and a fastener such as a bolt.

In this embodiment, the second frame is supported on the base 2, and the second frame includes four reinforcing members, each of which is disposed corresponding to one of the reinforcing walls to support each of the reinforcing walls. Each reinforcing member includes a second supporting column 4 extending vertically along the length direction, and a plurality of the second supporting columns 4 are sequentially arranged along the extending direction array of the first supporting column 31. Wherein, the upper bracket 5 is fixedly connected with and supported on the second support column 4. Through supporting along vertical extension's second support column 4 can make the reinforced wall can not receive the gravity of upper bracket 5 to when solving reinforced wall and bearing gravity, dislocation can appear each other, slide when vertical first support column 31 can be because of gravity and proof box 1's power, thereby reach the purpose of better atress. In addition, in this embodiment, when viewed from the outer peripheral side of any reinforcing wall, one of the reinforcing members at least includes a second supporting column 4 located at one end of the first supporting column 31 and a second supporting column 4 located at the other end of one end of the first supporting column 31, and the second supporting column 4 is sandwiched between the base 2 and the upper bracket 5, so that when the first supporting column 31 is subjected to unbalanced force, the first supporting column is supported so that the two ends of the first supporting column in the length direction do not slide or shift. Preferably, the reinforcing component comprises three second supporting columns 4 which are arranged at equal intervals when viewed from the outer peripheral side of any reinforcing wall, so as to achieve the purpose of enabling the reinforcing wall to be stressed evenly and supporting the upper bracket 5 stably. Wherein the test chamber 1 comprises two adjacent first press plates 11 and two adjacent second press plates 12, and the first press plates 11 and the second press plates 12 are in a quadrilateral structure when viewed in the vertical direction. The first presser plate 11 and the second presser plate 12 are disposed on the inner peripheral side of the reinforcing wall.

Referring to fig. 1 and 3, the underground engineering freezing test system includes a water injection device 7 and a water discharge device having a water discharge port provided at a lower side of test soil to discharge seepage water downward; the water injection device 7 is communicated with a water source and comprises a plurality of water outlets, and the water outlets are arranged at intervals along the vertical direction to inject water into the test soil at different depths so as to change the humidity of the test soil at different depths. Through the humidity that changes the test soil of the different degree of depth to realize the infiltration volume and the infiltration pressure of the soil of simulation different positions, be used for making it can simulate the influence of the soil of different humidity or dryness to freezing the effect.

The underground engineering freezing test system further comprises a light source device, a shooting device and a data acquisition device, the test box 1 and the test soil are of a transparent structure, the light source device comprises a laser source and a filter, the filter converts light of the laser source into a surface light source and projects the surface light source onto the test soil, the shooting device is used for displacement change inside the test soil when the freezing device C freezes the test soil through the cold air inlet pipe, and the data acquisition device comprises a displacement sensor, a pressure sensor and an osmometer which are arranged inside the test soil. And the displacement sensor, the pressure sensor, the osmometer and the shooting device are respectively connected with the computer B through electric signals. The imaging device is provided corresponding to the position of the observation port 32.

The data acquisition device of the underground engineering freezing test system further comprises a heater and a temperature sensor, wherein the heater and the temperature sensor can be embedded in positions of different depths of the test soil and used for heating the test soil and acquiring the temperature of the test soil. The geothermal temperature of the soil at different depths is simulated by heating the test soil at different positions, and the temperature of the soil at different depths is controlled by the heater, the temperature sensor and the temperature sensor. The device is matched with a water injection device 7 and a water drainage device to obtain the displacement and pressure change of test soil with different humidity and temperature in the freezing process or through sectional freezing.

The underground engineering freezing test system also comprises a hydraulic mechanism A with an oil guide loop A1, wherein the hydraulic mechanism A is respectively communicated with the pressing device, the first driving piece 84 and the second driving piece. Include upper bracket 5 and support in upper bracket 5 and be used for the vertical pressure loading mechanism 51 of exerting pressure from top to bottom to experimental soil, upper bracket 5 supports on the strengthening mechanism.

Preferably, referring to fig. 1 to 3, and fig. 7 and 8, the upper bracket 5 includes a plurality of cross members 54, and a support plate assembly fixed to the cross members 54, wherein the plurality of cross members 54 are fixedly connected to each other. The support plate assembly comprises a first support plate 53 for supporting the vertical pressure loading mechanism 51, and a second support plate 52 for fixedly connecting the second frame. In this embodiment, the cross beams 54 are arranged at intervals in the vertical orthogonal direction, the first support plate 53 is sandwiched between two adjacent cross beams 54 to connect and fix the cross beams 54, and the second support plate 52 is fixed to the first support plate 53 or the cross beam 54 and extends downward to fix the upper end of the second frame, that is, fixed to the upper end of the second support column 4.

Preferably, the cross beam 54, the first support plate 53 and the second support plate 52 can be fixedly connected to each other through a right-angle connector 55, and the two first support columns 31 respectively located on two adjacent reinforced walls can be fixedly connected to each other through a right-angle connector 55.

Preferably, with reference to fig. 1 to 3, the pressing device includes a side loading mechanism 6 supported on the reinforcing mechanism, and the side loading mechanism 6 is connected with a second pressing plate 12 to push the second pressing plate 12 to move. The side loading mechanism 6 comprises a first side loading mechanism 6 in a first direction and a second side loading mechanism 6 in a second direction, wherein the first side loading mechanism 6 and the second side loading mechanism 6 are arranged corresponding to the orientation of two adjacent first press plates 11. The hydraulic mechanism a is respectively communicated with the vertical pressure loading mechanism 51, the first lateral loading mechanism 6 and the second lateral loading mechanism 6, the first direction and the second direction form a vertical orthogonal direction, the first lateral loading mechanism 6 comprises a first loading member, the first loading member is respectively provided with four first pressure loading pieces, two first pressure loading pieces are respectively arranged at intervals along the vertical direction (namely the up-down direction), and the other two first pressure loading pieces are vertically arranged between the two first pressure loading pieces and are arranged at intervals along the second direction relative to the two first pressure loading pieces. The second lateral loading mechanism 6 includes second loading members, each of the second loading members has four second pressure loading parts, two of the second pressure loading parts are vertically (i.e., in the up-down direction) spaced from each other, and the remaining two second pressure loading parts are vertically located between the two second pressure loading parts and are spaced from the two second pressure loading parts along the first direction.

Through the configuration mode of the first loading member and the second loading member, the sequential loading of the test soil at different positions can be adjusted, so that the pressure distribution of the underground soil can be more accurately simulated. For example, the first pressure loading members are sequentially operated from bottom to top, so that the lower side of the loading plate firstly moves to load pressure on the test soil, then the first pressure loading members above the loading plate are operated to load pressure on the test soil, and finally the vertical pressure loading mechanism 51 loads pressure downwards, so that the test soil can simulate the pressure distribution of the soil at different depths. It can be understood that, with the first pressure-loading members or the second pressure-loading members arranged on one side surface, the pressure distribution of the test soil at different depths can be simulated more realistically than in the case where only one pressure-loading member is provided. It will be appreciated that in other embodiments, the number of first pressure-loading members in one lateral direction is not limited to only four, but may be plural, and the number of second pressure-loading members in one lateral direction is not limited to only four, but may be plural.

In other embodiments, the first loading member may comprise only one first loading member, the second loading member may comprise only one second loading member, and the first loading member and the second loading member may be simulated by integrally pressing the adjacent two sides of the test soil.

In other embodiments, the first lateral loading mechanism 6 includes two oppositely disposed first loading members and the second lateral loading mechanism 6 includes two oppositely disposed second loading members.

Preferably, the first and second pressure loading members are fixedly supported on the first support column 31, the first pressure loading member passing through the reinforcing wall to fixedly connect with the second pressing plate 12. Wherein, a mounting hole for the first pressure loading piece or the second pressure loading piece to pass through and support is opened on the reinforced wall corresponding to the second press plate 12.

Preferably, the height of the first frame 3, the first pressing plate 11 and the second pressing plate 12 in the vertical direction is smaller than that of the second frame, the cold air pipe seat is supported on the second frame, and the cold air pipe component can extend into the containing chamber 13 from the upper side of the first pressing plate 11 and/or the second pressing plate 12 and is placed in the test soil. Alternatively, the light from the light source device can be incident from the upper side of the first pressing plate 11 and/or the second pressing plate 12 to be incident into the transparent test soil.

Preferably, referring to fig. 3, 4 and 5, the underground engineering freezing test system further comprises a tunneling mechanism 8, wherein the tunneling mechanism 8 is used for excavating part of the test soil in the test box 1 to form a tunnel. Referring to fig. 1, 2, 3, 4 and 5, the tunneling mechanism 8 includes a support frame 81, a shield assembly, and a first driving element 84 supported on the support frame 81, the shield assembly includes a cylinder 82 and a rotary screw 83 sleeved in the cylinder 82, and the first driving element 84 is used for driving the shield assembly to move relative to the support frame 81; the shield assembly comprises a second driving piece for driving the rotary digging screw 83 to rotate so as to dig the test soil. The rotary screw 83 is formed by a long rod at the center and a helical blade arranged on the outer periphery of the long rod.

Preferably, the excavating mechanism 8 comprises a rotary support member 86 and a discharge channel 85, and the rotary support member 86 and the discharge channel 85 are supported on the support frame 81 and used for discharging the test soil from the discharge channel 85, so as to achieve the purpose of discharging the excavated test soil.

Preferably, the heading mechanisms 8 are respectively arranged in the outer spaces of two adjacent reinforced walls, and preferably, two heading mechanisms 8 are arranged in the outer spaces of the reinforced walls on each side to simulate the heading scene of the double-track tunnel. It will be appreciated that in other embodiments the space outside the reinforcing wall on each side can be provided with one or more than two ripping mechanisms 8. The excavation through holes on the two second pressing plates 12 are staggered in the vertical direction corresponding to the two adjacent second pressing plates 12, so that an excavation scene (i.e. a tunneling scene) of a tunnel with an upper line and a lower line can be simulated.

The underground engineering freeze test system includes pressure sensors configured on the first pressure loading member, the second pressure loading member, and the vertical pressure loading mechanism 51, which can be electrically coupled to the computer B to send a loading pressure value. The vertical pressure loading mechanism 51 includes a plurality of vertical pressure loading members, the first pressure loading member, the second pressure loading member and the vertical pressure loading member are respectively constituted by oil hydraulic cylinders, the hydraulic mechanism a has an oil guiding loop a1 for communicating the first pressure loading member, the second pressure loading member and the vertical pressure loading member, and the first pressure loading member, the second pressure loading member and the vertical pressure loading member are respectively and electrically coupled to a computer B. The oil guide loop A1 is provided with a hydraulic pump, a pressure control valve, a reversing valve, an overflow valve and an unloading overflow valve so as to control the rated working pressure and loading pressure of the first pressure loading piece, the second pressure loading piece and the vertical pressure loading piece and control the first pressure loading piece, the second pressure loading piece and the vertical pressure loading piece to sequentially execute loading actions. The computer B can be equipped with control and data acquisition software, such as GDSLAB software, to acquire the operating states and operating parameters of the pressure sensor, the hydraulic pump, the pressure control valve, the reversing valve, the relief valve, and the unloading relief valve.

With reference to fig. 1 to 8, the underground engineering freezing test system provided by the present invention can be implemented with the following steps:

and S100, filling test soil into the test box 1. The test soil is prepared from fused silica sand and a sucrose solution, wherein the particle diameter of the fused silica sand is 0.5-5mm, the concentration of the sucrose solution is that 198-205g of sucrose is dissolved in 100ml of purified water, and the refractive index of the test soil is 1.333-1.504. In other embodiments, the test soil is prepared from fused silica sand and calcium bromide solution, or amorphous silica powder and mineral oil, or amorphous silica powder, silica gel and brine. The test soil prepared from the fused quartz sand and the sucrose solution can overcome the defects that solutions in other preparation schemes are irritant, toxic or oily, and achieves the purpose of better simulating the properties of sandy soil by taking out the oily solution under the condition of ensuring safety.

S200, water seepage pressure data of the test soil are obtained through a osmometer, and when the water seepage pressure data reach a preset water seepage pressure threshold value, the test soil is frozen through a refrigerating device C, wherein the refrigerating device C comprises a plurality of cold air imbedding pipes communicated with cold air pipe seats, cold air outlets of the cold air imbedding pipes are arranged at different positions of the test soil, and the cold air imbedding pipes are sequentially opened to enable the different positions of the test soil to be frozen according to different sequences.

S300, acquiring displacement data of the test soil and pressure data inside the test soil at different positions through the displacement sensor and the pressure sensor, and transmitting the displacement data and the pressure data to the computer B for data analysis through electric signals.

And S400, acquiring a displacement change image of the test soil through a camera device, and transmitting the image to a computer B through an electric signal for image analysis.

And S500, analyzing the displacement data, the pressure data, the water seepage pressure data and the image of the test soil through the computer B.

With reference to fig. 1 to 8, the underground engineering freezing test system provided by the present invention can further perform the following steps:

S100A, test soil is filled in the test chamber 1.

And S200A, injecting water into the test soil through the water injection device 7 to change the humidity of the soil at different positions.

And S300A, heating the test soil through a heater to change the temperature of the soil at different positions.

S400A, through displacement sensor, pressure sensor, temperature sensor and osmometer obtain the displacement volume data of the experimental soil of different positions department, the inside pressure data of experimental soil, the inside temperature distribution data of experimental soil and the infiltration pressure data of experimental soil to carry out data analysis in transmitting displacement volume data, pressure data, temperature distribution data and infiltration pressure data to computer B through the electric signal.

And S500A, acquiring water seepage pressure data of the test soil through a osmometer, and freezing the test soil through a freezing device C when the water seepage pressure data reaches a preset water seepage pressure threshold value. The freezing device C comprises a plurality of cold air inlet pipes communicated with cold air pipe seats, cold air outlets of the cold air inlet pipes are arranged at different positions of the test soil, and the cold air inlet pipes are sequentially opened to freeze the different positions of the test soil according to different sequences.

S600A, acquiring displacement data of the test soil and pressure data inside the test soil at different positions through the displacement sensor and the pressure sensor, and transmitting the displacement data and the pressure data to the computer B for data analysis through electric signals.

And S700A, analyzing the displacement data, the pressure data, the water seepage pressure data and the image of the test soil through the computer B. The displacement sensor, the pressure sensor, the temperature sensor and the osmometer are electrically connected with a computer B through cables, and control and data acquisition software, such as GDSLAB software, is installed in the computer B to acquire displacement data, pressure data inside the test soil, water seepage pressure data of the test soil, internal temperature distribution of the test soil and displacement change images and analyze the data and the images. For example, by changing the temperature, the influence of the temperature of the soil at different depths on the freezing effect and the freezing speed in the freezing process can be obtained, and the expansion rate of the test soil and the like can be obtained by combining the temperature and the freezing speed of the soil with water seepage pressure data.

Preferably, other structures or effects not mentioned in the third embodiment may be referred to the first or second embodiment.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.