阅读说明：本技术 一种用于测量冻土孔隙水压力变化的装置 (Device for measuring frozen soil pore water pressure change ) 是由 张莲海 杨成松 马巍 于 2021-08-18 设计创作，主要内容包括：公开了一种用于测量冻土孔隙水压力变化的装置,包括安装底座,下端能够安装在安装底座上的介质座以及下端能够安装在安装底座上且上端与介质座活动连接的渗透座；所述介质座包括介质基座以及设置在介质基座内的介质槽管；所述介质槽管内径为0.05～0.08mm,且介质槽管采用亲水材料；介质槽管内填充有界面水；本发明整体结构设计合理,利用介质槽管的特殊结构以及材质配合界面水能够有效地避免现有技术中存在的介质中易产生水泡导致的测量失效以及量程小的问题；利用界面水作为介质能够有效地避免对环境造成的污染问题；并且还搭配装置的整体结构实现较好的密封性,在实际的使用中具备更大的测量量程范围。(The device comprises an installation base, a medium seat of which the lower end can be installed on the installation base, and a permeation seat of which the lower end can be installed on the installation base and of which the upper end is movably connected with the medium seat; the medium seat comprises a medium base and a medium groove pipe arranged in the medium base; the inner diameter of the medium groove pipe is 0.05-0.08 mm, and the medium groove pipe is made of a hydrophilic material; the medium groove pipe is filled with interface water; the invention has reasonable integral structure design, and can effectively avoid the problems of measurement failure and small measuring range caused by easily generating bubbles in the medium in the prior art by utilizing the special structure and material of the medium groove pipe to match with interfacial water; the problem of environmental pollution can be effectively avoided by using interfacial water as a medium; and the better leakproofness is realized to the overall structure of still collocation device, has bigger measuring range scope in actual use.)

1. A device for measuring the change of pore water pressure of frozen soil comprises an installation base (1), a medium seat (2) with the lower end capable of being installed on the installation base (1), and a permeation seat (3) with the lower end capable of being installed on the installation base (1) and the upper end movably connected with the medium seat (2);

the mounting base (1) is characterized by comprising a mounting base (11) and a pressure sensor (12), wherein the upper end of the mounting base is provided with a mounting head (101), and the pressure sensor is embedded in the center of the upper surface of the mounting base (11); a first mounting groove (102) is formed in the inner side of the mounting head (101);

the medium seat (2) comprises a medium base (21) and a medium groove pipe (22), wherein the upper end of the medium base is provided with a permeation groove (201), the lower end of the medium base is provided with a pressure measurement groove (202), the medium groove pipe is arranged in the medium base (21), the upper port of the medium groove pipe is communicated with the permeation groove (201), and the lower port of the medium groove pipe is communicated with the pressure measurement groove (202);

the infiltration seat (3) comprises an infiltration base (31) and an infiltration head (32), wherein the upper end of the infiltration base is provided with a placing groove (301), the lower end of the infiltration base is provided with a second mounting groove (302), and the infiltration head is mounted in the placing groove (301);

the lower end of the penetrating base (31) can be movably arranged on the mounting base (11) through the second mounting groove (302) and the mounting head (101); the lower end of the medium base (21) can be movably mounted on the mounting base (11) through the side wall of the pressure measuring groove (202) and the first mounting groove (102), the medium base (21) is positioned in the permeation base (31), and the outer side wall of the upper end of the medium base (21) can be movably connected with the inner side wall of the permeation base (31); the lower end of the permeation head (32) is embedded in the permeation groove (201), and the upper end of the pressure sensor (12) is embedded in the pressure measurement groove (202);

sealing modules (4) are arranged at the joint of the medium base (21) and the mounting base (11) and the joint of the medium base (21) and the permeation base (31);

the inner diameter of the medium groove pipe (22) is 0.05-0.08 mm, and the medium groove pipe (22) is made of hydrophilic materials; the medium groove pipe (22) is filled with interface water.

2. The device according to claim 1, characterized in that the sealing module (4) is a sealing gasket, and the joint of the medium base (21) and the installation base (11) and the joint of the medium base (21) and the permeation base (31) are provided with sealing clamping grooves for clamping the sealing module (4).

3. The device according to claim 1, characterized in that the medium base (21) is in threaded connection with the mounting base (11) and the infiltration base (31), respectively, and the sealing module (4) is in particular a sealing thread compound applied on the threads.

4. The device according to claim 1, characterized in that the exposed parts of the mounting base (11) and the penetrating base (31) are provided with sealing layers.

5. Device according to claim 1, characterized in that the inner wall of the medium channel tube (22) is provided with a super-hydrophilic coating, in particular nano-TiO₂And (4) coating.

6. The device according to claim 1, further comprising an auxiliary device (5); the auxiliary device (5) comprises a mounting base (51), a plate (520) which is arranged on the mounting base (51) and can form a box body (52), and a sample placing unit which is arranged on the mounting base (1); the sample placing unit comprises a bottom sealing plate (53) arranged on a mounting base (51), a sample placing pipe (54) with the bottom end capable of being movably connected with the bottom sealing plate (53) and used for placing a soil sample to be tested, a top sealing plate (55) which is arranged at the top of a box body (52), capable of being movably connected with the top end of the sample placing pipe (54) and internally provided with a refrigerating fluid coil pipe, and two groups of refrigerating fluid circulating temperature control devices which are respectively used for controlling the temperature of the bottom sealing plate (53) and the top sealing plate (55);

and a measuring hole (540) is formed in the side wall of the sample placing pipe (54).

7. The apparatus according to claim 1, wherein said auxiliary device (5) further comprises a water replenishing device for replenishing water to the inside of the sample-placing tube (54).

Technical Field

The invention relates to the technical field of frozen soil parameter measuring devices, in particular to a device for measuring the change of pore water pressure of frozen soil.

Background

The freeze-thaw action is used as a main disease for the engineering construction of the alpine regions, and brings great problems for the engineering construction of the alpine regions. Researches show that the influence of the freezing and thawing action on the structure and the strength of the soil body is closely related to the change process of the pore water pressure in the freezing and thawing process.

Therefore, the research on the change of pore water pressure in the freezing and thawing process becomes an important parameter for researching the freezing and thawing effect. However, since the measurement of the pore water pressure of the soil body in the frozen state of the soil body has been a certain technical difficulty, people usually use liquid substances which are not easily frozen at negative temperature, such as ethanol, simethicone, n-decane, and the like, as media to measure the change of the pore water pressure of the frozen soil at present, but the substances all pollute the soil, so that a specific standard and a device for measuring the change of the pore water pressure of the frozen soil have not been provided in the prior art. For this reason, there is a need for a device for measuring changes in pore water pressure of frozen earth.

Disclosure of Invention

The invention aims to provide a device for measuring the pressure change of pore water of frozen soil.

The technical scheme of the invention is as follows: a device for measuring the change of pore water pressure of frozen soil comprises an installation base, a medium seat of which the lower end can be installed on the installation base, and a permeation seat of which the lower end can be installed on the installation base and of which the upper end is movably connected with the medium seat;

the mounting base comprises a mounting base with a mounting head arranged at the upper end and a pressure sensor embedded in the center of the upper surface of the mounting base; a first mounting groove is formed in the inner side of the mounting head;

the medium seat comprises a medium base with an upper end provided with a permeation groove and a lower end provided with a pressure measuring groove and a medium groove pipe which is arranged in the medium base, wherein an upper port of the medium base is communicated with the permeation groove, and a lower port of the medium base is communicated with the pressure measuring groove;

the infiltration seat comprises an infiltration base and an infiltration head, wherein the upper end of the infiltration base is provided with a placing groove, the lower end of the infiltration base is provided with a second mounting groove, and the infiltration head is mounted in the placing groove;

the lower end of the penetration base can be movably arranged on the mounting base through the second mounting groove and the mounting head; the lower end of the medium base can be movably arranged on the mounting base through the side wall of the pressure measuring groove and the first mounting groove, the medium base is positioned in the permeation base, and the outer side wall of the upper end of the medium base can be movably connected with the inner side wall of the permeation base; the lower end of the permeation head is embedded in the permeation groove, and the upper end of the pressure sensor is embedded in the pressure measurement groove;

sealing modules are arranged at the joint of the medium base and the installation base and the joint of the medium base and the permeation base;

the inner diameter of the medium groove pipe is 0.05-0.08 mm, and the medium groove pipe is made of a hydrophilic material; the medium groove pipe is filled with interface water; the surface of a hydrophilic material is utilized to interact with water molecules, the interaction force range can reach the micron order at the maximum, water in the range is generally called as interfacial water, and the physical and mechanical properties of the water are greatly different from the volume of water, so that the inner diameter of a medium groove pipe is set to be 0.05-0.08 mm, the medium water filled in the medium groove pipe can be used as the interfacial water, the lower limit of air pockets formed under negative pressure is reduced, the measurement range of the device can be effectively expanded, and the problem of environmental pollution caused by other media can be effectively avoided by adopting the interfacial water as a force transmission medium.

As one aspect of the invention, the sealing module is specifically a sealing gasket, and the joint of the medium base and the installation base and the joint of the medium base and the permeation base are both provided with a sealing clamping groove for clamping the sealing module; the sealing gasket is arranged to effectively seal the connecting ports of the mounting base, the medium base and the permeation base, so that the problem of inaccurate measurement of equipment caused by insufficient sealing can be effectively avoided in actual measurement of frozen soil pore water pressure.

As one aspect of the invention, the medium base is connected with the installation base and the permeation base through threads respectively, and the sealing module is specifically a sealing thread glue coated on the threads; the connection contact surfaces of the mounting base, the medium base and the penetrating base can be further effectively sealed by the sealing thread glue.

As one aspect of the invention, the exposed parts of the mounting base and the permeation base are provided with sealing layers; the sealing layer is arranged at the exposed part, so that the whole sealing performance of the device can be effectively guaranteed, pore water in the frozen soil can only enter the device through the penetration head, and the measurement accuracy can be further improved.

As one aspect of the invention, the inner wall of the medium groove pipe is provided with a super-hydrophilic coating, and the super-hydrophilic coating is specifically nano TiO₂Coating; the super-hydrophilic coating can effectively ensure that the surface of the super-hydrophilic coating can interact with water molecules, and interfacial water is filled in the medium groove pipe.

As one aspect of the invention, the device further comprises an auxiliary device; the auxiliary device comprises a mounting base, a plate which is arranged on the mounting base and can form a box body, and a sample placing unit which is arranged on the mounting base; the sample placing unit comprises a bottom sealing plate arranged on the mounting base, a sample placing pipe, a top sealing plate and two groups of refrigerating fluid circulating temperature control devices, wherein the bottom end of the sample placing pipe can be movably connected with the bottom sealing plate and is used for placing a soil sample to be tested; a measuring hole is formed in the side wall of the sample placing pipe; can utilize auxiliary device to realize off-site measurement's sampling measurement scene, and can change temperature parameter through it, further can study the change that frozen soil pore water pressure receives the temperature influence.

As an aspect of the present invention, the auxiliary device further includes a water replenishing device for replenishing water to the inside of the sample-placing tube; the water replenishing device can be used for replenishing water for the soil sample in the freezing and thawing process in the test.

Compared with the prior art, the invention has the beneficial effects that: the invention has reasonable integral structure design, and can effectively avoid the problems of measurement failure and small measuring range caused by easy bubble generation in the medium in the prior art by utilizing the special structure of the medium trough pipe and the material matched with the medium water; in addition, interfacial water is used as a medium for measuring the pore water pressure of the frozen soil instead of substances such as ethanol, n-decane and dimethyl silicon oil, so that the problem of environmental pollution during measurement can be effectively avoided; and the better leakproofness is realized to the overall structure of still collocation device, has bigger measuring range scope in actual use.

Drawings

FIG. 1 is a schematic structural view of embodiment 1 of the present invention;

FIG. 2 is an exploded view of example 1 of the present invention;

FIG. 3 is a schematic structural view of embodiment 2 of the present invention;

FIG. 4 is an exploded view of example 2 of the present invention;

FIG. 5 is an exploded view of example 6 of the present invention;

the device comprises a mounting base 1, a mounting head 101, a mounting base 102, a first mounting groove 11, a mounting base 12, a pressure sensor 2, a medium seat 201, a permeation groove 202, a pressure measuring groove 21, a medium seat 22, a medium groove pipe 3, a permeation seat 301, a placement groove 302, a second mounting groove 31, a permeation seat 32, a permeation head 4, a sealing module 5, an auxiliary device 51, a mounting base 51, a box 52, a plate 520, a bottom sealing plate 53, a sample placement pipe 54, a measuring hole 540 and a top sealing plate 55.

Detailed Description

Example 1:

as shown in fig. 1 and 2, the device for measuring frozen soil pore water pressure change comprises an installation base 1, a medium seat 2 with a lower end capable of being installed on the installation base 1, and a penetration seat 3 with a lower end capable of being installed on the installation base 1 and an upper end movably connected with the medium seat 2;

the mounting base 1 comprises a mounting base 11 with a mounting head 101 arranged at the upper end and a pressure sensor 12 embedded in the center of the upper surface of the mounting base 11; a first mounting groove 102 is arranged on the inner side of the mounting head 101;

the medium seat 2 comprises a medium base 21 with an upper end provided with a permeation groove 201 and a lower end provided with a pressure measuring groove 202, and a medium groove pipe 22 which is arranged in the medium base 21, wherein the upper port of the medium groove pipe is communicated with the permeation groove 201, and the lower port of the medium groove pipe is communicated with the pressure measuring groove 202;

the infiltration seat 3 comprises an infiltration base 31 with a placing groove 301 at the upper end and a second installing groove 302 at the lower end, and an infiltration head 32 installed in the placing groove 301;

the lower end of the infiltration base 31 can be movably arranged on the installation base 11 through the second installation groove 302 and the installation head 101; the lower end of the medium base 21 can be movably mounted on the mounting base 11 through the side wall of the pressure measuring groove 202 and the first mounting groove 102, the medium base 21 is positioned in the permeation base 31, and the outer side wall of the upper end of the medium base 21 can be movably connected with the inner side wall of the permeation base 31; the lower end of the permeation head 32 is embedded in the permeation groove 201, and the upper end of the pressure sensor 12 is embedded in the pressure measurement groove 202;

sealing modules 4 are arranged at the joint of the medium base 21 and the installation base 11 and the joint of the medium base 21 and the permeation base 31; the medium base 21 is connected with the mounting base 11 and the permeation base 31 through threads respectively, and the sealing module 4 is specifically sealing thread glue coated on the threads, wherein the sealing thread glue is specifically pipeline thread sealant with the model number of XK 569;

the inner diameter of the medium groove pipe 22 is 0.05mm, and the medium groove pipe 22 is made of hydrophilic materials, particularly metal chromium; the medium tank pipe 22 is filled with interface water.

Example 2:

the difference from example 1 is: the inner diameter of the medium groove pipe 22 is 0.05 mm;

as shown in fig. 3 and 4, the sealing module 4 is specifically a sealing gasket, and sealing grooves for clamping the sealing module 4 are disposed at the joints of the medium base 21 and the installation base 11 and at the joints of the medium base 21 and the permeation base 31.

Example 3:

the difference from example 1 is: the inner diameter of the medium groove pipe 22 is 0.06 mm; sealing layers are arranged on the exposed parts of the mounting base 11 and the permeation base 31.

Example 4:

the difference from example 1 is: the inner diameter of the medium groove pipe 22 is 0.08 mm; the medium base 21 is connected with the mounting base 11 and the permeation base 31 through threads respectively, and the sealing module 4 is specifically sealing thread glue coated on the threads, wherein the sealing thread glue is specifically pipeline thread sealant with the model number of XK 569; sealing modules 4 are arranged at the joint of the medium base 21 and the installation base 11 and the joint of the medium base 21 and the permeation base 31; the sealing module 4 is specifically a sealing gasket, and sealing clamping grooves for clamping the sealing module 4 are arranged at the joint of the medium base 21 and the mounting base 11 and at the joint of the medium base 21 and the permeation base 31; the exposed parts of the mounting base 11 and the penetrating base 31 are provided with sealing layers, and the sealing layers are specifically made of MatriXbond3533PUR electronic bonding structural adhesive.

Example 5:

the difference from example 1 is: the inner diameter of the medium groove pipe 22 is 0.08 mm; the inner wall of the medium groove pipe 22 is provided with a super-hydrophilic coating which is specifically nano TiO₂And (4) coating.

Example 6:

the difference from example 1 is: as shown in fig. 5, further comprises an auxiliary device 5; the auxiliary device 5 comprises a mounting base 51, a plate 520 which is mounted on the mounting base 51 and can form a box 52, and a sample placing unit which is mounted on the mounting base 1; the sample placing unit comprises a bottom sealing plate 53 arranged on the mounting base 51, a sample placing pipe 54 with the bottom end capable of being movably connected with the bottom sealing plate 53 and used for placing a soil sample to be tested, a top sealing plate 55 which is arranged on the top of the box body 52 and capable of being movably connected with the top end of the sample placing pipe 54 and is internally provided with a refrigerating fluid coil pipe in a coiled manner, and two groups of refrigerating fluid circulating temperature control devices which are respectively used for controlling the temperature of the bottom sealing plate 53 and the temperature of the top sealing plate 55 and water supplementing devices which are used for supplementing water to the interior of the sample placing pipe 54; a measuring hole 540 is formed in the side wall of the sample placing pipe 54; wherein the plate 520 is made of organic glass; the specimen placement tube 54 is embodied as a plexiglas jar.

It should be noted that: the measuring holes 540 are used for measuring the temperature and the pressure of different parts of the sample soil, the specific number is set according to the actual measurement, and no specific limitation is made, and 6 measuring holes 540 used for measuring the temperature of different parts of the sample soil and 3 measuring holes 540 used for measuring the pressure of different parts of the sample soil are set in the embodiment.

Experimental example:

1) carrying out field test on a certain Tibet railway line in the northern foot river area of the Tibet plateau: the device of the present embodiment 1 to 5 and a device for measuring pore water pressure of frozen soil are used to perform multiple detections on the same detection point (the probe embedding position of the detection point is silty clay, the embedding depth is 20cm, the temperature is-1.0 ℃, and the water content is 98%) in batches, and record 10 groups of batch data randomly, and after sampling at the location, the device of the present embodiment 6 is used to perform multiple measurements and record 10 groups of data randomly, wherein the specific measurement results are shown in table 1;

table 1: frozen soil pore water pressure value measured by devices 1-6 and control group in the embodiment

And (4) conclusion: as can be seen from the data in Table 1, compared with the prior art, the devices in the embodiments 1 to 6 of the present invention have better stability when testing the pore water pressure of the frozen soil.

2) Taking a soil sample along a certain Tibet railway in the northern foot river area of the Tibet plateau to perform indoor test: the devices of the embodiments 1 to 5 and some devices for measuring the pore water pressure of the frozen soil are utilized to measure in batches under the condition of changing the parameters of the soil sample (the temperature (minus 10 ℃), the saturation (100 percent to 5 percent) and the load (less than 3MPa) of the soil sample are changed in variable parameters), and the measurement range table shown in the table 2 is obtained;

table 2: in the embodiments 1-5 of the present invention, the range values of the devices and the control group are measured after the soil sample parameters are changed

Grouping	Measuring range
		Example 1	-2MPa～3MPa
Example 2	-2MPa～3MPa
		Example 3	-2MPa～3MPa
Example 4	-2MPa～3MPa
		Example 5	-2MPa～3MPa
Control group	-0.1MPa～3MPa

And (4) conclusion: as can be seen from the data in Table 2, compared with the prior art, the devices of the embodiments 1 to 5 of the present invention have a larger measurement range.