CN-121994614-A - Triaxial shear strength testing method for sealing ice plug body of circumferential seam of sewage disposal tunnel

Abstract

The invention discloses a triaxial shear strength test method for a pollution discharge tunnel circumferential seam plugging ice plug body, which comprises the steps of S1, cutting a cylindrical sponge sample from medium density sponge, S2, sleeving a rubber membrane on the side surface of the cylindrical sponge sample, mounting a bottom steel support at the bottom, S3, injecting water into the cylindrical sponge sample in the rubber membrane to obtain a cylindrical sponge sample after water injection, S4, respectively freezing the cylindrical sponge sample after water injection in a test block curing box at different set temperatures to form a cylindrical sponge ice sample, wherein the set temperatures are respectively the same as the average temperature of the ice plug body to be formed by liquid nitrogen freezing construction, S5, placing the cylindrical sponge ice sample in a triaxial test machine, and performing triaxial shear strength test under set confining pressure to determine the shear strength of the cylindrical sponge ice under a simulated working condition, and S6, according to test data of S5, obtaining triaxial shear characteristics of the cylindrical sponge ice at different set temperatures. The invention solves the technical dilemma that in-situ shear test can not be carried out on the ice plug body on site.

Inventors

• HUANG BAOLONG
• FU CAI
• GAO WEI
• HAN YUFU
• NING FANGBO
• HAN SHENGMING
• ZHANG FUJIAN
• DONG SHIZHUO
• YANG MINGHONG

Assignees

• 北京中煤矿山工程有限公司

Dates

Publication Date

20260508

Application Date

20260213

Claims (10)

1. 1. The triaxial shear strength testing method for the sealing ice plug body of the circumferential seam of the sewage disposal tunnel is characterized by comprising the following steps of: S1, sample preparation Cutting a cylindrical sponge sample from the medium-density sponge for later use; s2, packaging Sleeving a rubber film on the side surface of the cylindrical sponge sample, exposing the upper bottom surface and the lower bottom surface, installing the bottom of the rubber film in a bottom steel support, and closing the lower end of the bottom steel support and opening the upper end of the bottom steel support so that the bottom of the rubber film stretches into the bottom steel support; S3, water injection Injecting water into the cylindrical sponge sample from the upper bottom surface of the cylindrical sponge sample to enable the cylindrical sponge sample to fully absorb water to obtain the cylindrical sponge sample after water injection, S4, freezing and curing The cylindrical sponge sample after water injection is placed in a test block curing box and is frozen at different set temperatures to form a cylindrical sponge ice sample, wherein the set temperatures are respectively the same as the average temperature of an ice plug body to be formed by liquid nitrogen freezing construction in a pollution discharge tunnel circumferential seam blocking and freezing working condition, and the cylindrical sponge ice sample is used for simulating the ice plug body to be formed by liquid nitrogen freezing construction in the pollution discharge tunnel circumferential seam blocking and freezing working condition; S5, mounting the top of the rubber film in a top steel support in a triaxial shear test, then placing a cylindrical sponge ice sample in a triaxial test machine, wherein the upper end of the top steel support is closed, and the lower end of the top steel support is open so that the top of the rubber film stretches into the top steel support; S6, analyzing results According to the data of S5, triaxial shear characteristics of the cylindrical sponge ice sample at different set temperatures are obtained.
2. 2. The method for testing triaxial shear strength of a blow-down tunnel circumferential seam plugging ice plug body according to claim 1, wherein in S1, the cylindrical sponge sample has a size of Φ61.8mm×100deg.mm.
3. 3. The method for testing triaxial shear strength of a blow-down tunnel girth plugging ice plug body according to claim 1, wherein in S1, the density of the medium density sponge is 20kg/m 3 , and an electrothermal cutter and a ring cutter are adopted to sample the medium density sponge.
4. 4. The triaxial shear strength testing method for the ice plug body for sealing the circumferential seam of the sewage disposal tunnel according to claim 1, wherein in S2, a fastening mechanism is arranged at the joint of the bottom steel support and the rubber membrane, and in S5, the fastening mechanism is arranged at the joint of the top steel support and the rubber membrane.
5. 5. The method for testing triaxial shear strength of a sealing ice plug body of a circumferential seam of a sewage disposal tunnel according to claim 4, wherein the fastening mechanism is a rubber band.
6. 6. The method for testing triaxial shear strength of a sealing ice plug body for a circumferential seam of a sewage disposal tunnel according to claim 1, wherein in the step S4, the set temperatures are-15 ℃, -20 ℃ and-25 ℃ respectively.
7. 7. The method for testing triaxial shear strength of a blow-down tunnel girth plugging ice plug according to claim 6, wherein a plurality of cylindrical sponge ice samples are prepared at each temperature for parallel testing.
8. 8. The method for testing triaxial shear strength of the ice plug body for sealing the circumferential seam of the sewage tunnel according to claim 1, wherein in S5, axial loading is performed in a constant axial strain rate control mode, and confining pressure is determined according to the height of the water level in the sewage tunnel to be treated.
9. 9. The method for testing triaxial shear strength of a drain tunnel circumferential seam plugging ice plug body according to claim 8, wherein the axial strain rate is 0.5-1%/min.
10. 10. The method for testing triaxial shear strength of a drain tunnel circumferential seam plugging ice plug body according to claim 9, wherein the axial strain rate is 1%/min.

Description

Triaxial shear strength testing method for sealing ice plug body of circumferential seam of sewage disposal tunnel Technical Field The invention relates to the technical field of testing triaxial shear strength. In particular to a triaxial shear strength testing method for a sealing ice plug body of a circumferential seam of a sewage disposal tunnel. Background A drain tunnel in a certain place is to be plugged by forming an ice plug body by adopting a liquid nitrogen freezing method, a coil pipe of a liquid nitrogen freezer is fixed on a semicircular steel plate, and the steel plate has the functions of fixing, heat conduction and water flow blocking. The width of the circumferential seam between the outer edges of the steel plates and the inner walls of the tunnels is 80mm, and the circumferential seam is sealed by wrapping sponge at the outer edges of the steel plates, so that heat convection between the water body in the to-be-frozen area and the peripheral water body is reduced, and the formation of frozen bodies is accelerated. The triaxial shear strength of the ice plug body is required to be obtained in order to find out the mechanical properties of the ice plug body formed after the sponge is frozen so as to provide necessary parameters and basis for the liquid nitrogen freezing construction of the tunnel, and the in-situ shear test of the ice plug body cannot be carried out on site because the sewage tunnel is filled with sewage. Therefore, the invention provides a triaxial shear strength testing method for the sealing of the circular seam of the sewage disposal tunnel and the ice plug body. Disclosure of Invention Therefore, the technical problem to be solved by the invention is to provide the triaxial shear strength test method for the sealing ice plug body of the circumferential seam of the sewage disposal tunnel, and the obtained data can be used for guiding the construction of the sealing working condition of the circumferential seam of the sewage disposal tunnel, so that the serious risk of the construction of freezing and sealing the sewage pipeline by liquid nitrogen is reduced, and the safety of the construction of freezing and sealing the sewage by liquid nitrogen is ensured. In order to solve the technical problems, the invention provides the following technical scheme: The triaxial shear strength testing method for the sealing ice plug body of the circumferential seam of the sewage disposal tunnel comprises the following steps: S1, sample preparation Cutting a cylindrical sponge sample from the medium-density sponge for later use; s2, packaging Sleeving a rubber film on the side surface of the cylindrical sponge sample, exposing the upper bottom surface and the lower bottom surface, installing the bottom of the rubber film in a bottom steel support, and closing the lower end of the bottom steel support and opening the upper end of the bottom steel support so that the bottom of the rubber film stretches into the bottom steel support; S3, water injection Injecting water into the cylindrical sponge sample in the rubber membrane from the upper bottom surface of the cylindrical sponge sample, so that the cylindrical sponge sample fully absorbs water to obtain a cylindrical sponge sample after water injection; S4, freezing maintenance The cylindrical sponge sample after water injection is placed in a test block curing box and is frozen at different set temperatures to form a cylindrical sponge ice sample, wherein the set temperatures are respectively the same as the average temperature of an ice plug body to be formed by liquid nitrogen freezing construction in a pollution discharge tunnel circumferential seam blocking and freezing working condition, and the cylindrical sponge ice sample is used for simulating the ice plug body to be formed by liquid nitrogen freezing construction in the pollution discharge tunnel circumferential seam blocking and freezing working condition; s5, triaxial shear test The method comprises the steps of installing the top of a rubber film in a top steel support, placing a cylindrical sponge ice sample in a triaxial test machine, closing the upper end of the top steel support and opening the lower end of the top steel support so that the top of the rubber film stretches into the top steel support, keeping the cylindrical sponge ice sample in a non-consolidation and non-drainage state under set confining pressure, axially loading until the cylindrical sponge ice sample is destroyed, and recording axial load and deformation data in real time; S6, analyzing results And (3) according to the test data of the step S5, obtaining triaxial shear characteristics of the cylindrical sponge ice sample at different set temperatures. The application uses a medium-density sponge, the water absorption efficiency, the freezing expansion force and the mechanical strength of the medium-density sponge are more in accordance with the freezing and plugging site working condition of a se