Reinforcement method of shield receiving end

Abstract

The invention discloses a reinforcement method for a shield receiving end, comprising: step 1, pouring plain concrete on the periphery of the shield receiving end to build a continuous underground wall; step 2, in the continuous underground wall, freezing the area within the shield tunnel outline and between the shield tunnel outline and the continuous underground wall by setting a liquid nitrogen freezing device to form a frozen reinforcement area also in a concave shape, annularly freezing the soil within the shield tunnel outline by liquid nitrogen, and horizontally freezing the soil between the shield tunnel outline and the continuous underground wall by liquid nitrogen; step 3, before the shield machine arrives, removing the second freezing part, keeping the first freezing part in working state and continuing to freeze, and stopping the second freezing part and removing the second freezing part after the shield machine has completely passed the shield receiving end position. The invention greatly reduces the possibility of water and sand gushing when the shield end receives, plays an effect of preventing collapse, and has excellent reinforcement effect.

Description

Technical Field

[0001] The invention belongs to the technical field of shield construction and relates to a method for reinforcing a receiving end of a shield. Background Art

[0002] With the continuous development of urban rail transit, underground space has been rapidly developed and utilized, and shield construction in high-water-rich strata has been rapidly promoted and applied. During the shield construction process, the end of the shield tunnel needs to be reinforced. If the reinforcement quality is not good, water leakage is likely to occur, and in severe cases, soil collapse will occur, resulting in failure of the shield to start receiving. The artificial freezing method has good development prospects in the process of shield tunneling in and out of the tunnel due to its advantages such as high freezing strength and good water-stopping properties. However, in the frozen area of ​​this method, when the shield machine cuts and passes through the frozen soil, if the end reinforcement effect is not good, it is likely to cause sand and water gushing along the direction of the shield machine's advance. Although excessive reinforcement has a good freezing effect, it increases the freezing cost and resource consumption. Therefore, it is urgent to improve the reinforcement effect of the shield receiving end without increasing costs and resource consumption. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide a method for reinforcing a receiving end of a shield machine.

[0005] The technical solution provided by the present invention is:

[0006] A method for reinforcing a receiving end of a shield machine comprises the following steps:

[0007] Step 1: pouring plain concrete around the receiving end of the shield machine to build a continuous underground wall, wherein the continuous underground wall is in a concave shape and the opening faces the advancing direction of the shield machine;

[0008] Step 2: In the continuous underground wall, the area within the shield tunnel outline and the area between the shield tunnel outline and the continuous underground wall are frozen by setting a liquid nitrogen freezing device to form a frozen reinforcement area also in the shape of a concave character, wherein the soil within the shield tunnel outline is annularly frozen by liquid nitrogen, and the soil between the shield tunnel outline and the continuous underground wall is horizontally frozen by liquid nitrogen.

[0009] The liquid nitrogen freezing device comprises: a first freezing part, which comprises a plurality of freezing pipes, wherein the plurality of freezing pipes are horizontally arranged in the area between the outline of the shield tunnel and the continuous underground wall, and each of the freezing pipes is arranged at intervals of 0.6-1.2 meters in both horizontal and vertical spacings.

[0010] A second freezing section includes a plurality of freezing rings, which are arranged within the outline of the shield tunnel, each of which includes a plurality of freezing ring tubes, which are circular and concentrically arranged in a direction perpendicular to the advancing direction of the shield, and each freezing ring is arranged at intervals of 1-2 meters;

[0011] The first freezing part and the second freezing part are connected to the liquid nitrogen system respectively, and liquid nitrogen is continuously introduced into each of them until the surrounding detection temperature reaches -15°C or lower, and liquid nitrogen is continuously introduced to keep the surrounding parts of the shield tunnel contour line in a frozen state;

[0012] Step 3: Before the shield machine arrives, the second freezing part within the shield tunnel contour is removed, and the first freezing part remains in working condition and continues to freeze. When the shield machine has completely passed the shield receiving end position, the working condition of the second freezing part is stopped and the second freezing part is removed.

[0013] Preferably, in the method for reinforcing the receiving end of the shield machine, step 2 further includes: connecting adjacent freezing pipes respectively through a plurality of horizontally arranged stainless steel hoses to form a through passage of the first freezing device.

[0014] Preferably, in the reinforcement method for the receiving end of the shield machine, in step 2, in each of the freezing ring parts, adjacent freezing ring pipes are connected in sequence through a plurality of stainless steel hoses, so that the freezing ring parts form a through passage.

[0015] Preferably, the method for reinforcing the receiving end of the shield machine further comprises:

[0016] Step 4: From the ground downwards, in the area of ​​the vault within the outline of the shield tunnel, a three-axis mixing pile reinforcement structure is set inside the continuous underground wall, and is overlapped with the wall of the continuous underground wall by high-pressure jet grouting piles for reinforcement.

[0017] Preferably, in the method for reinforcing the receiving end of a shield machine, the first freezing part further comprises:

[0018] The liquid inlet pipe and the liquid outlet pipe respectively connected to the two ends of the freezing pipe are arranged corresponding to the freezing pipe in the direction of the shield advance. The rear of each freezing pipe is connected to the liquid inlet pipe, and the front is connected to the liquid outlet pipe. The liquid inlet pipe and the liquid outlet pipe are both stainless steel hoses.

[0019] Preferably, in the method for reinforcing the receiving end of the shield machine, in step one, steel sheet piles are also fixed in the vertical direction in front of the position of the receiving end of the shield machine, and the steel sheet piles are located in front of the continuous underground wall.

[0020] Preferably, in the method for reinforcing the receiving end of the shield machine, in step 2, the pressure of the liquid nitrogen injection is 0.05-0.15 MPa.

[0021] The present invention has at least the following beneficial effects:

[0022] The method of the present invention reinforces the surrounding soil of the shield receiving end in layers, horizontally freezes the land around the shield end through the first freezing part, annularly freezes the area within the shield tunnel contour through the second freezing part, freezes the surrounding soil through two different freezing trajectories, and freezes the soil of the shield receiving end in different dimensions and angles in two ways, so that the freezing effect is better, the water-stopping effect is achieved, and the strength of the surrounding soil is improved. At the same time, it is also helpful for later grouting or reinforcement. When the shield machine arrives, the second freezing part is removed, and the first freezing part remains in working condition, which greatly reduces the possibility of water and sand gushing when the shield end is receiving, and has the effect of preventing collapse, and the reinforcement effect is excellent.

[0023] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0024] The present invention is described in further detail below so that those skilled in the art can implement it according to the description.

[0025] It should be noted that, in the description of the present invention, terms such as "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" to indicate directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0026] The present invention provides a method for reinforcing a receiving end of a shield machine, comprising the following steps:

[0027] Step 1: pouring plain concrete around the receiving end of the shield machine to build a continuous underground wall, wherein the continuous underground wall is in a concave shape and the opening faces the advancing direction of the shield machine;

[0028] Step 2: In the continuous underground wall, the area within the shield tunnel outline and the area between the shield tunnel outline and the continuous underground wall are frozen by setting a liquid nitrogen freezing device to form a frozen reinforcement area also in the shape of a concave character, wherein the soil within the shield tunnel outline is annularly frozen by liquid nitrogen, and the soil between the shield tunnel outline and the continuous underground wall is horizontally frozen by liquid nitrogen.

[0029] Furthermore, the liquid nitrogen freezing device comprises: a first freezing part, which comprises a plurality of freezing pipes, wherein the plurality of freezing pipes are horizontally arranged in the area between the outline of the shield tunnel and the continuous underground wall, and each of the freezing pipes is arranged at intervals of 0.6-1.2 meters in both horizontal and vertical spacings,

[0030] A second freezing section includes a plurality of freezing rings, which are arranged within the outline of the shield tunnel, each of which includes a plurality of freezing ring tubes, which are circular and concentrically arranged in a direction perpendicular to the advancing direction of the shield, and each freezing ring is arranged at intervals of 1-2 meters;

[0031] The first freezing part and the second freezing part are connected to the liquid nitrogen system respectively, and liquid nitrogen is continuously introduced into each of them until the surrounding detection temperature reaches -15°C or lower, and liquid nitrogen is continuously introduced to keep the surrounding parts of the shield tunnel contour line in a frozen state;

[0032] Step 3: Before the shield machine arrives, the second freezing part within the shield tunnel contour is removed, and the first freezing part remains in working condition and continues to freeze. When the shield machine has completely passed the shield receiving end position, the working condition of the second freezing part is stopped and the second freezing part is removed.

[0033] The method of the present invention reinforces the surrounding soil of the shield receiving end in layers, horizontally freezes the land around the shield end through the first freezing part, and annularly freezes the area within the shield tunnel contour through the second freezing part. The surrounding soil is frozen by two different freezing trajectories, which plays a water-stopping role and improves the strength of the surrounding soil. At the same time, it is also helpful for later grouting or reinforcement. When the shield machine arrives, the second freezing part is removed, and the first freezing part remains in working condition, which greatly reduces the possibility of water and sand gushing when the shield end is receiving, plays an effect of preventing collapse, and has an excellent reinforcement effect.

[0034] In one technical solution of the present invention, preferably, in step 2, the method further comprises: connecting adjacent freezing pipes through a plurality of horizontally arranged stainless steel hoses, so that the first freezing device forms a through passage. This is conducive to the unified monitoring and management of the freezing state of the entire area, and is also convenient for controlling the pressure and flow rate of the liquid nitrogen input, so as to achieve a uniform freezing state.

[0035] In one of the technical solutions of the present invention, preferably, in step 2, in each freezing part, adjacent freezing ring pipes are sequentially connected through a plurality of stainless steel hoses, so that the freezing ring parts form a through passage, which is convenient for the entire installation and removal of the second freezing part, and also convenient for the unified adjustment of the freezing state in the area within the outline of the shield tunnel.

[0036] In one of the technical solutions of the present invention, as a preference, it also includes:

[0037] Step 4: From the ground down to the area of ​​the vault within the shield tunnel outline, a three-axis mixing pile reinforcement structure is set inside the continuous underground wall, and high-pressure jet grouting piles are overlapped with the wall of the continuous underground wall for reinforcement. This step is to reinforce the area from the ground down to the vault within the shield tunnel outline, which can be performed simultaneously with other steps without affecting each other. The reinforcement of this difference allows the shield end to receive the surrounding soil to be fully reinforced, improving the reinforcement effect.

[0038] In one technical solution of the present invention, preferably, the first freezing unit further comprises:

[0039] The liquid inlet pipe and the liquid outlet pipe corresponding to the freezing pipe are connected to the two ends of the freezing pipe in the direction of the shield advance. The rear of each freezing pipe is connected to the liquid inlet pipe, and the front is connected to the liquid outlet pipe. Both the liquid inlet pipe and the liquid outlet pipe are stainless steel hoses. The advantage of this connection method is that each freezing pipe can be managed separately, the temperature of each part in its area can be monitored in real time, and refined management can be carried out, which is conducive to saving resources and reducing energy consumption.

[0040] In one of the technical solutions of the present invention, preferably, in step 1, a steel sheet pile is fixed in the vertical direction in front of the receiving end of the shield, and the steel sheet pile is located in front of the continuous underground wall. The steel sheet pile is used to further enhance the reinforcement effect of the peripheral area.

[0041] In one technical solution of the present invention, preferably, in step 2, the liquid nitrogen is introduced at a pressure of 0.05-0.15 MPa. Under this pressure condition, the freezing effect on the soil can be ensured, and at the same time, the freezing efficiency can be improved to avoid a long freezing period.

[0042] In order to enable those skilled in the art to better understand the technical solution of the present invention, the following embodiments are provided for illustration:

[0043] A method for reinforcing a receiving end of a shield machine comprises the following steps:

[0044] Step 1: pour plain concrete on the periphery of the shield receiving end to build a continuous underground wall, and fix steel sheet piles in the vertical direction in front of the shield receiving end. The continuous underground wall is concave in shape, and the opening faces the forward direction of the shield machine; the steel sheet piles are located in front of the continuous underground wall.

[0045] Step 2: In the continuous underground wall, the area within the shield tunnel outline and the area between the shield tunnel outline and the continuous underground wall are frozen by setting a liquid nitrogen freezing device to form a frozen reinforcement area also in the shape of a concave character, wherein the soil within the shield tunnel outline is annularly frozen by liquid nitrogen, and the soil between the shield tunnel outline and the continuous underground wall is horizontally frozen by liquid nitrogen.

[0046] Furthermore, the liquid nitrogen freezing device comprises: a first freezing part, which comprises a plurality of freezing pipes, wherein the plurality of freezing pipes are horizontally arranged in the area between the outline of the shield tunnel and the continuous underground wall, and each of the freezing pipes is arranged at intervals of 0.6-1.2 meters in both horizontal and vertical spacings,

[0047] A second freezing section includes a plurality of freezing rings, which are arranged within the outline of the shield tunnel, each of which includes a plurality of freezing ring tubes, which are circular and concentrically arranged in a direction perpendicular to the advancing direction of the shield, and each freezing ring is arranged at intervals of 1-2 meters;

[0048] The first freezing part and the second freezing part are connected to the liquid nitrogen system respectively, and liquid nitrogen is continuously introduced into each of them at a pressure of 0.12MPa until the ambient detection temperature reaches -15°C or lower, and liquid nitrogen is continuously introduced to maintain the freezing state of the parts around the outline of the shield tunnel; Step 2 also includes: connecting adjacent freezing pipes through multiple horizontally arranged stainless steel hoses to form a through passage for the first freezing part device. In each of the freezing parts, adjacent freezing ring pipes are sequentially connected through multiple stainless steel hoses to form a through passage for the freezing ring part.

[0049] Step 3: Before the shield machine arrives, the second freezing part within the shield tunnel contour is removed, and the first freezing part remains in working condition and continues to freeze. When the shield machine has completely passed the shield receiving end position, the working condition of the second freezing part is stopped and the second freezing part is removed.

[0050] Step 4: From the ground downwards, in the area of ​​the vault within the outline of the shield tunnel, a three-axis mixing pile reinforcement structure is set inside the continuous underground wall, and high-pressure jet grouting piles are used to overlap the wall of the continuous underground wall for reinforcement.

[0051] The number of modules and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention are obvious to those skilled in the art.

[0052] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for reinforcing a receiving end of a shield machine, characterized in that: The steps include: Step 1: pouring plain concrete around the receiving end of the shield machine to build a continuous underground wall, wherein the continuous underground wall is in a concave shape and the opening faces the advancing direction of the shield machine; Step 2: In the continuous underground wall, the area within the shield tunnel outline and the area between the shield tunnel outline and the continuous underground wall are frozen by setting a liquid nitrogen freezing device to form a frozen reinforcement area also in the shape of a concave character, wherein the soil within the shield tunnel outline is annularly frozen by liquid nitrogen, and the soil between the shield tunnel outline and the continuous underground wall is horizontally frozen by liquid nitrogen. Furthermore, the liquid nitrogen freezing device comprises: a first freezing part, which comprises a plurality of freezing pipes, wherein the plurality of freezing pipes are horizontally arranged in the area between the outline of the shield tunnel and the continuous underground wall, and each of the freezing pipes is arranged at intervals of 0.6-1.2 meters in both horizontal and vertical spacings, A second freezing section includes a plurality of freezing rings, which are arranged within the outline of the shield tunnel, each of which includes a plurality of freezing ring tubes, which are circular and concentrically arranged in a direction perpendicular to the advancing direction of the shield, and each freezing ring is arranged at intervals of 1-2 meters; The first freezing part and the second freezing part are connected to the liquid nitrogen system respectively, and liquid nitrogen is continuously introduced into each of them until the surrounding detection temperature reaches -15°C or lower, and liquid nitrogen is continuously introduced to keep the surrounding parts of the shield tunnel contour line in a frozen state; Step 3: Before the shield machine arrives, the second freezing part within the shield tunnel contour is removed, and the first freezing part remains in working condition and continues to freeze. When the shield machine has completely passed the shield receiving end position, the working condition of the second freezing part is stopped and the second freezing part is removed.

2. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: The second step also includes: connecting adjacent freezing pipes respectively through a plurality of horizontally arranged stainless steel hoses to form a through passage in the first freezing device.

3. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: In step 2, in each of the freezing parts, adjacent freezing ring pipes are connected in sequence through a plurality of stainless steel hoses, so that the freezing ring parts form a through passage.

4. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: Also includes: Step 4: From the ground downwards, in the area of ​​the vault within the outline of the shield tunnel, a three-axis mixing pile reinforcement structure is set inside the continuous underground wall, and is overlapped with the wall of the continuous underground wall by high-pressure jet grouting piles for reinforcement.

5. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: The first freezing unit further comprises: The liquid inlet pipe and the liquid outlet pipe respectively connected to the two ends of the freezing pipe are arranged corresponding to the freezing pipe in the direction of the shield advance. The rear of each freezing pipe is connected to the liquid inlet pipe, and the front is connected to the liquid outlet pipe. The liquid inlet pipe and the liquid outlet pipe are both stainless steel hoses.

6. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: In step one, steel sheet piles are also fixed in the vertical direction in front of the receiving end position of the shield machine, and the steel sheet piles are located in front of the continuous underground wall.

7. The method for reinforcing the receiving end of a shield machine as claimed in claim 1, characterized in that: In step 2, the liquid nitrogen introduction pressure is 0.05-0.15 MPa.