Reinforcement method of soil columns between tunnels

Abstract

The present invention relates to a method for reinforcing a soil column between tunnels, comprising the following steps: (1) determining the construction position of a prestressed tension through-anchor on the surface of the soil column; (2) drilling a plurality of through holes; (3) installing the prestressed tension through-anchor in the holes; (4) installing a reinforcement grid frame on two surfaces of the soil column respectively; (5) using a strong steel mesh to completely cover the two end faces of the soil column respectively; (6) tensioning the prestressed tension through-anchor on the surface of the soil column respectively; (7) after tensioning, spraying high-performance concrete on the two surfaces and end faces of the soil column. The method of the present invention can significantly enhance the stability of the soil column in the tunnel, has a reasonable reinforcement design, is simple to construct, has high construction efficiency, and has good use effect, and can provide effective, stable, and reliable support for the tunnel.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering construction, and in particular to a method for reinforcing soil columns between tunnels. Background Art

[0002] During the tunnel construction process in loess geology, in order to effectively control the surface subsidence caused by tunnel construction and the stability of the geology in the construction area, some auxiliary construction measures are usually adopted during tunnel construction, which can effectively avoid the collapse of the tunnel excavation face and reduce excessive deformation of the strata in the construction area.

[0003] At present, the construction and reinforcement design of earth-pin columns in tunnel engineering have become the main design focus and difficulty. The design of the tunnel section should make the surrounding rock around the tunnel have fewer tensile stress areas to ensure the stability of the earth-pin columns. In order to ensure the stability of the geology during tunnel excavation and reduce adverse factors such as geological deformation and blasting vibration caused by small tunnel spacing, the earth-pin columns should be reinforced before and after excavation to improve their bearing capacity. This is the key to the design and construction of earth-pin columns.

[0004] However, there are very few reports on the reinforcement of soil columns during tunnel construction in the prior art, and the reinforcement construction of soil columns is blind and unsafe, which easily causes construction safety hazards. Therefore, it is very necessary to optimize and improve the reinforcement construction of soil columns. Summary of the invention

[0005] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides a method for reinforcing soil columns between tunnels. The method of the present invention can significantly enhance the stability of soil columns between tunnels, has a reasonable reinforcement design, is simple to construct, has high construction efficiency, and has good use effect, and can effectively, stably, and reliably support the tunnel.

[0006] To achieve the above object, the present invention provides a method for reinforcing soil columns between tunnels, comprising the following steps:

[0007] (1) According to the construction design requirements, the construction position of the prestressed tension through-bolt is determined on the surface of the soil column formed between the excavated tunnels;

[0008] (2) Drilling a plurality of through holes according to the above-mentioned construction position, which penetrate the entire thickness of the soil clamping column and are arranged in a matrix in the length and height direction of the soil clamping column;

[0009] (3) installing the prestressed tension through-anchor rod in the hole, with both ends of the prestressed tension through-anchor rod protruding from two surfaces of the soil clamping column respectively;

[0010] (4) The reinforcement grid frames are respectively installed on the two surfaces of the soil clamping column, and the reinforcement grid frames are respectively sleeved on the ends of the prestressed tension through-anchor rods protruding from the surface of the soil clamping column, and locked by a locking device to fix the reinforcement grid frames on the surface of the soil clamping column;

[0011] (5) Strong steel mesh is used to completely cover the two end faces of the soil clamping column, and the two ends of the strong steel mesh are hung on the ends of the corresponding prestressed tension through-anchor rods protruding from the surface of the soil clamping column. One end of the strong steel mesh is also provided with a tension adjustment device to adjust the overall covering force of the strong steel mesh on the end face of the soil clamping column;

[0012] (6) tensioning the prestressed tension through-anchor rods on the surfaces of the soil clamping columns respectively, and locking them after tensioning so that they exert an anchoring force on the soil clamping columns;

[0013] (7) After tensioning is completed, high-performance concrete is sprayed on the two surfaces and end faces of the soil-clamping column to completely cover the reinforcement grid frame, the ends of the prestressed tensioning anchor rods protruding from the surface of the soil-clamping column, and the strong steel mesh, forming a smooth concrete appearance.

[0014] Preferably, in step (1), the surface refers to the surface of the soil clamping column facing the inner space of the tunnel; in step (5), the end surface refers to the surface of the soil clamping column flush with the tunnel entrance.

[0015] In any of the above schemes, it is preferred that in step (2), the axial center spacings between any two of the plurality of through holes are equal.

[0016] In any of the above schemes, it is preferred that in step (4), the reinforcement grid frame is welded by multiple transverse L-shaped steels and multiple longitudinal steel strips, and a through hole is provided at the connection between the L-shaped steels and the steel strips, and the end of the prestressed tension through-anchor protruding from the surface of the soil clamping column passes through the through hole.

[0017] In any of the above schemes, it is preferred that in step (5), the tensioning adjustment device includes a mounting frame, a plurality of driving cylinders and a tension detection unit; the plurality of driving cylinders are evenly spaced and fastened to the mounting frame in the vertical direction, and their movable ends are respectively connected to the corresponding tensile steel strands, and the other ends of the tensile steel strands are connected to one end of the strong steel mesh, and each tensile steel strand is accommodated in a corresponding guide tube for easy tensile guidance, and the guide tube is arranged on the mounting frame; the tension detection unit includes a pressure sensing unit connected to the driving cylinder, a signal receiver connected to the pressure sensing unit, and a control unit.

[0018] In any of the above schemes, it is preferred that in step (6), half of the prestressed tensioned through-anchor rods are tensioned on the surface of one side of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced apart in pairs; after the above tensioning is completed, the other half of the prestressed tensioned through-anchor rods are tensioned on the surface of the other side of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced apart in pairs.

[0019] In any of the above schemes, it is preferred that in step (6), after the tensioning is completed, grouting is injected into the prestressed tension-through anchor rod, and after the grouting is completed, a grouting stop plug is promptly installed, and then a locking mechanism is installed for locking; the slurry mix ratio is: cement: sodium silicate = 2:1.

[0020] In any of the above schemes, it is preferred that when the thickness of the soil-binding column is ≤1.2W, the thickness of the sprayed high-performance concrete is 25-30cm, and the thickness of the reinforced grid frame is 10-15cm; when 1.2W<the thickness of the soil-binding column<2W, the thickness of the sprayed high-performance concrete is 20-22cm, and the thickness of the reinforced grid frame is 5-8cm; wherein W is the width of the excavation section of a single-hole tunnel.

[0021] The beneficial effects of the present invention are:

[0022] 1. The method of the present invention can significantly enhance the stability of the tunnel soil column, has a reasonable reinforcement design, is simple to construct, has high construction efficiency, and has good use effect, and can provide effective, stable, and reliable support for the tunnel.

[0023] 2. The construction method of the present invention avoids the use of advanced horizontal rotary jet grouting piles commonly used in the prior art to reinforce the soil-clamped columns, prevents the impact on the easily damaged areas of the soil-clamped columns, and adopts a new reinforcement method to better ensure the reinforcement of the soil-clamped columns, further enhancing the overall strength of the structure.

[0024] 3. The present invention uses prestressed tension through-anchor rods in combination with grouting to strengthen the anchoring of the internal structure of the soil-clamped column, so that it has better anti-deformation ability and ensures the structural strength of the soil-clamped column; the use of a reinforced grid frame connects the prestressed tension through-anchor rods and the soil-clamped column into a whole, thereby improving the integrity of the structure; the hanging strong steel mesh makes the overall structure of the easily damaged area of ​​the soil-clamped column more solid and the reinforcement effect is better; the sprayed high-performance concrete further strengthens the overall strength of the soil-clamped column.

[0025] 4. The construction method of the present invention adopts the overall coordination of reinforcement grid frame, prestressed tension through anchor rods, grouting, strong steel mesh and high-performance concrete to comprehensively reinforce the entire soil column, making its overall structural strength more stable, and the construction is simple, safe and fast, which greatly improves and enhances the construction effect, and has significant economic and social effects. DETAILED DESCRIPTION

[0026] The technical solution of the present application will be described in detail below in conjunction with the specific implementation methods of the present application, but the following examples are only for understanding the present invention. The embodiments in the present application and the features in the embodiments can be combined with each other, and the present application can be implemented in a variety of different ways as defined and covered by the claims.

[0027] Example 1

[0028] A method for reinforcing soil columns between tunnels, comprising the following steps:

[0029] (1) According to the construction design requirements, the construction position of the prestressed tension through-bolt is determined on the surface of the soil column formed between the excavated tunnels;

[0030] (2) Drilling a plurality of through holes according to the above-mentioned construction position, which penetrate the entire thickness of the soil clamping column and are arranged in a matrix in the length and height direction of the soil clamping column;

[0031] (3) installing the prestressed tension through-anchor rod in the hole, with both ends of the prestressed tension through-anchor rod protruding from two surfaces of the soil clamping column respectively;

[0032] (4) The reinforcement grid frames are respectively installed on the two surfaces of the soil clamping column, and the reinforcement grid frames are respectively sleeved on the ends of the prestressed tension through-anchor rods protruding from the surface of the soil clamping column, and locked by a locking device to fix the reinforcement grid frames on the surface of the soil clamping column;

[0033] (5) Strong steel mesh is used to completely cover the two end faces of the soil clamping column, and the two ends of the strong steel mesh are hung on the ends of the corresponding prestressed tension through-anchor rods protruding from the surface of the soil clamping column. One end of the strong steel mesh is also provided with a tension adjustment device to adjust the overall covering force of the strong steel mesh on the end face of the soil clamping column;

[0034] (6) tensioning the prestressed tension through-anchor rods on the surfaces of the soil clamping columns respectively, and locking them after tensioning so that they exert an anchoring force on the soil clamping columns;

[0035] (7) After tensioning is completed, high-performance concrete is sprayed on the two surfaces and end faces of the soil-clamping column to completely cover the reinforcement grid frame, the ends of the prestressed tensioning anchor rods protruding from the surface of the soil-clamping column, and the strong steel mesh, forming a smooth concrete appearance.

[0036] In step (1), the surface refers to the surface of the soil clamping column facing the inner space of the tunnel; in step (5), the end surface refers to the surface of the soil clamping column that is flush with the tunnel entrance.

[0037] In step (2), the axial spacing between each of the plurality of through holes is equal.

[0038] In step (4), the reinforcement grid frame is welded by a plurality of transverse L-shaped steels and a plurality of longitudinal steel strips, and a through hole is provided at the connection between the L-shaped steels and the steel strips, and the end of the prestressed tension through-anchor protruding from the surface of the soil clamping column passes through the through hole.

[0039] In step (5), the tensioning adjustment device includes a mounting frame, a plurality of driving cylinders and a tension detection unit; the plurality of driving cylinders are evenly spaced and fastened to the mounting frame in the vertical direction, and their movable ends are respectively connected to the corresponding tensile steel strands, and the other end of the tensile steel strands is connected to one end of the strong steel mesh, and each tensile steel strand is accommodated in a corresponding guide tube for easy tensile guidance, and the guide tube is arranged on the mounting frame; the tension detection unit includes a pressure sensing unit connected to the driving cylinder, a signal receiver connected to the pressure sensing unit, and a control unit.

[0040] In step (6), half of the prestressed tensioned through-anchor rods are tensioned on one side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time; after the above tensioning is completed, the other half of the prestressed tensioned through-anchor rods are tensioned on the other side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time.

[0041] In step (6), after the tensioning is completed, grouting is injected into the prestressed tension-through anchor rod. After the grouting is completed, a grouting stopper is promptly installed, and then a locking mechanism is installed to lock it. The grouting ratio is: cement: sodium silicate = 2:1.

[0042] When the thickness of the soil-binding column is ≤1.2W, the thickness of the sprayed high-performance concrete is 25cm and the thickness of the reinforced grid frame is 15cm; when 1.2W<the thickness of the soil-binding column<2W, the thickness of the sprayed high-performance concrete is 20cm and the thickness of the reinforced grid frame is 8cm; where W is the width of the excavation section of the single-hole tunnel.

[0043] Example 2

[0044] A method for reinforcing soil columns between tunnels, comprising the following steps:

[0045] (1) According to the construction design requirements, the construction position of the prestressed tension through-bolt is determined on the surface of the soil column formed between the excavated tunnels;

[0046] (2) Drilling a plurality of through holes according to the above-mentioned construction position, which penetrate the entire thickness of the soil clamping column and are arranged in a matrix in the length and height direction of the soil clamping column;

[0047] (3) installing the prestressed tension through-anchor rod in the hole, with both ends of the prestressed tension through-anchor rod protruding from two surfaces of the soil clamping column respectively;

[0048] (4) The reinforcement grid frames are respectively installed on the two surfaces of the soil clamping column, and the reinforcement grid frames are respectively sleeved on the ends of the prestressed tension through-anchor rods protruding from the surface of the soil clamping column, and locked by a locking device to fix the reinforcement grid frames on the surface of the soil clamping column;

[0049] (5) Strong steel mesh is used to completely cover the two end faces of the soil clamping column, and the two ends of the strong steel mesh are hung on the ends of the corresponding prestressed tension through-anchor rods protruding from the surface of the soil clamping column. One end of the strong steel mesh is also provided with a tension adjustment device to adjust the overall covering force of the strong steel mesh on the end face of the soil clamping column;

[0050] (6) tensioning the prestressed tension through-anchor rods on the surfaces of the soil clamping columns respectively, and locking them after tensioning so that they exert an anchoring force on the soil clamping columns;

[0051] (7) After tensioning is completed, high-performance concrete is sprayed on the two surfaces and end faces of the soil-clamping column to completely cover the reinforcement grid frame, the ends of the prestressed tensioning anchor rods protruding from the surface of the soil-clamping column, and the strong steel mesh, forming a smooth concrete appearance.

[0052] In step (1), the surface refers to the surface of the soil clamping column facing the inner space of the tunnel; in step (5), the end surface refers to the surface of the soil clamping column that is flush with the tunnel entrance.

[0053] In step (2), the axial spacing between each of the plurality of through holes is equal.

[0054] In step (4), the reinforcement grid frame is welded by a plurality of transverse L-shaped steels and a plurality of longitudinal steel strips, and a through hole is provided at the connection between the L-shaped steels and the steel strips, and the end of the prestressed tension through-anchor protruding from the surface of the soil clamping column passes through the through hole.

[0055] In step (5), the tensioning adjustment device includes a mounting frame, a plurality of driving cylinders and a tension detection unit; the plurality of driving cylinders are evenly spaced and fastened to the mounting frame in the vertical direction, and their movable ends are respectively connected to the corresponding tensile steel strands, and the other end of the tensile steel strands is connected to one end of the strong steel mesh, and each tensile steel strand is accommodated in a corresponding guide tube for easy tensile guidance, and the guide tube is arranged on the mounting frame; the tension detection unit includes a pressure sensing unit connected to the driving cylinder, a signal receiver connected to the pressure sensing unit, and a control unit.

[0056] In step (6), half of the prestressed tensioned through-anchor rods are tensioned on one side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time; after the above tensioning is completed, the other half of the prestressed tensioned through-anchor rods are tensioned on the other side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time.

[0057] In step (6), after the tensioning is completed, grouting is injected into the prestressed tension-through anchor rod. After the grouting is completed, a grouting stopper is promptly installed, and then a locking mechanism is installed to lock it. The grouting ratio is: cement: sodium silicate = 2:1.

[0058] When the thickness of the soil-binding column is ≤1.2W, the thickness of the sprayed high-performance concrete is 30cm and the thickness of the reinforced grid frame is 10cm; when 1.2W<the thickness of the soil-binding column<2W, the thickness of the sprayed high-performance concrete is 22cm and the thickness of the reinforced grid frame is 5cm; where W is the width of the excavation section of the single-hole tunnel.

[0059] Example 3

[0060] A method for reinforcing soil columns between tunnels, comprising the following steps:

[0061] (1) According to the construction design requirements, the construction position of the prestressed tension through-bolt is determined on the surface of the soil column formed between the excavated tunnels;

[0062] (2) Drilling a plurality of through holes according to the above-mentioned construction position, which penetrate the entire thickness of the soil clamping column and are arranged in a matrix in the length and height direction of the soil clamping column;

[0063] (3) installing the prestressed tension through-anchor rod in the hole, with both ends of the prestressed tension through-anchor rod protruding from two surfaces of the soil clamping column respectively;

[0064] (4) The reinforcement grid frames are respectively installed on the two surfaces of the soil clamping column, and the reinforcement grid frames are respectively sleeved on the ends of the prestressed tension through-anchor rods protruding from the surface of the soil clamping column, and locked by a locking device to fix the reinforcement grid frames on the surface of the soil clamping column;

[0065] (5) Strong steel mesh is used to completely cover the two end faces of the soil clamping column, and the two ends of the strong steel mesh are hung on the ends of the corresponding prestressed tension through-anchor rods protruding from the surface of the soil clamping column. One end of the strong steel mesh is also provided with a tension adjustment device to adjust the overall covering force of the strong steel mesh on the end face of the soil clamping column;

[0066] (6) tensioning the prestressed tension through-anchor rods on the surfaces of the soil clamping columns respectively, and locking them after tensioning so that they exert an anchoring force on the soil clamping columns;

[0067] (7) After tensioning is completed, high-performance concrete is sprayed on the two surfaces and end faces of the soil-clamping column to completely cover the reinforcement grid frame, the ends of the prestressed tensioning anchor rods protruding from the surface of the soil-clamping column, and the strong steel mesh, forming a smooth concrete appearance.

[0068] In step (1), the surface refers to the surface of the soil clamping column facing the inner space of the tunnel; in step (5), the end surface refers to the surface of the soil clamping column that is flush with the tunnel entrance.

[0069] In step (2), the axial spacing between each of the plurality of through holes is equal.

[0070] In step (4), the reinforcement grid frame is welded by a plurality of transverse L-shaped steels and a plurality of longitudinal steel strips, and a through hole is provided at the connection between the L-shaped steels and the steel strips, and the end of the prestressed tension through-anchor protruding from the surface of the soil clamping column passes through the through hole.

[0071] In step (5), the tensioning adjustment device includes a mounting frame, a plurality of driving cylinders and a tension detection unit; the plurality of driving cylinders are evenly spaced and fastened to the mounting frame in the vertical direction, and their movable ends are respectively connected to the corresponding tensile steel strands, and the other end of the tensile steel strands is connected to one end of the strong steel mesh, and each tensile steel strand is accommodated in a corresponding guide tube for easy tensile guidance, and the guide tube is arranged on the mounting frame; the tension detection unit includes a pressure sensing unit connected to the driving cylinder, a signal receiver connected to the pressure sensing unit, and a control unit.

[0072] In step (6), half of the prestressed tensioned through-anchor rods are tensioned on one side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time; after the above tensioning is completed, the other half of the prestressed tensioned through-anchor rods are tensioned on the other side surface of the soil-clamping column, and the tensioned prestressed tensioned through-anchor rods are spaced two by two at this time.

[0073] In step (6), after the tensioning is completed, grouting is injected into the prestressed tension-through anchor rod. After the grouting is completed, a grouting stopper is promptly installed, and then a locking mechanism is installed to lock it. The grouting ratio is: cement: sodium silicate = 2:1.

[0074] When the thickness of the soil-binding column is ≤1.2W, the thickness of the sprayed high-performance concrete is 28cm and the thickness of the reinforced grid frame is 13cm; when 1.2W<the thickness of the soil-binding column<2W, the thickness of the sprayed high-performance concrete is 21cm and the thickness of the reinforced grid frame is 7cm; where W is the width of the excavation section of the single-hole tunnel.

[0075] Example 4

[0076] In this embodiment, a method for reinforcing soil columns between tunnels is the same as that in Embodiment 1.

[0077] In order to further improve the technical effect of the present invention, in this embodiment, the locking device is located on the end of the outer sleeve of the prestressed tension bolt, and the locking mechanism is located outside the locking device. The locking device can be a bolt, and the locking mechanism can be an anchor.

[0078] The strong steel mesh is made by the following steps:

[0079] (1) Straighten the steel bars, cut them into sections, and remove oxides and dirt from the steel bar surface;

[0080] (2) The steel bar is subjected to strong drawing and placed in a tempering furnace, heated to 550°C and kept warm for 3.5 hours for tempering. During this process, neon gas is introduced as a protective gas. The drawing-tempering process is repeated three times in succession. After the tempering is completed, the steel bar is cooled by air. Each drawing reduces the diameter of the steel bar by 1 mm. After that, two annealing treatments are carried out, each time heating to 480°C, holding for 1 hour, and then cooling at a rate of 20°C / min.

[0081] (3) The steel bars are straightened for the second time and then welded to form a strong steel mesh.

[0082] In the above steps, removing oxides and dirt on the surface of the steel bars means spraying nitric acid onto the steel bars through a high-pressure atomizing nozzle, leaving them at room temperature for 15 minutes, then heating them to 130°C, keeping them warm and leaving them for 10 minutes; then performing ultrasonic cleaning for 10-15 minutes, and then drying them.

[0083] The strong steel mesh is easy to manufacture, and can effectively improve the elasticity and toughness of the steel bar after tempering treatment, and can eliminate the residual stress of the steel bar after annealing treatment, stabilize the size, and reduce the tendency of deformation and cracking. The preparation process can effectively reduce the production cost; the strong steel mesh thus prepared has excellent performance and can well ensure the reinforcement effect of the soil column.

[0084] In step (5), the specific operation of tensioning the strong steel mesh is: hang one end of the strong steel mesh on the end of the corresponding prestressed tension through-anchor rod protruding from the surface of the soil clamping column, connect the tensile steel strand at the other end, and then connect it to the tensioning adjustment device, and temporarily fix the tensioning adjustment device on the other side surface of the soil clamping column. According to the design requirements, start the tensioning adjustment device to slowly tension the strong steel mesh, and monitor the tensioning process in real time through the tension detection unit. When the expected tensioning force is reached, stop the tensioning adjustment device and maintain the existing tensioning force, and hang the other end of the strong steel mesh on the end of the corresponding prestressed tension through-anchor rod protruding from the surface of the soil clamping column at an appropriate position to keep it in a tensioned state. Finally, remove the tensioning adjustment device to complete the tensioning construction.

[0085] The setting and use of the above-mentioned tensioning adjustment device can maintain the tensioning force required for reinforcing the soil-clamped column, and can guide the stretched steel strands during the tensioning process, thereby realizing the reliable operation of the tensioning construction; the tension detection unit can monitor the tensioning force of the stretched steel strands in real time, and automatically adjust the tensioning force, thereby realizing automatic monitoring and automatic correction, and improving safety and reliability.

[0086] Example 5

[0087] In this embodiment, a method for reinforcing soil columns between tunnels is the same as that in Embodiment 2.

[0088] In order to further improve the technical effect of the present invention, in this embodiment, the high-performance concrete includes cement, steel fiber, machine-made sand, gravel, gibbsite, microsilica powder, water, and an early strength agent; the weight ratio thereof is 10:2:13:5:2:6:15:0.5.

[0089] The high-performance concrete has high strength and can better ensure the overall reinforcement of the soil-stacked column. According to the compressive strength test in GB / T50081-2002 "Standard Method for Testing Mechanical Properties of Ordinary Concrete", the high-performance concrete was tested for 28d compressive strength. The results showed that its 28d compressive strength reached 69.3Mpa, and the structural strength performance was much better than the 30-50Mpa of concrete in the prior art.

[0090] The prestressed tension through-anchor rod comprises an outer sleeve and an inner tension rod, the end of the outer sleeve is provided with a grouting port, and the outer sleeve is provided with a plurality of evenly spaced grouting holes on the peripheral wall along the length direction; the inner tension rod is pivotally provided with a plurality of evenly spaced anchoring plates in the length direction, the anchoring plates in each group are arranged in an umbrella shape, and each anchoring plate is pivotally connected to a rated leg pivotally arranged on the grouting hole. The free end of the anchoring plate is in a cone shape, which is convenient for insertion into the soil clamping column.

[0091] In step (6), during tensioning, the prestressed tension through-anchor rod at one end is fastened to the surface of the soil clamping column, and the prestressed tension through-anchor rod at the other end is tensioned. The inner tension rod is tensioned to make it move slowly in the outer sleeve. During this process, the anchor plate gradually opens in an umbrella shape as the inner tension rod moves, and is inserted into the surrounding soil clamping column structure, thereby strengthening the anchoring effect. After tensioning is in place, grouting is performed into the outer sleeve through the grouting port. The slurry leaks out from multiple slurry outlet holes and can be consolidated with the soil clamping column after solidification. After grouting, the grouting stop plug is promptly installed to close the grouting port, and then the locking mechanism is installed to lock it, and the tensioning construction is completed.

[0092] The prestressed tension-through anchor rod and tensioning construction adopted in the present invention effectively enhance the shear resistance of the internal tension rod, and realize uniform diffusion of slurry to form a solid consolidation structure, thereby improving the strength of the internal structure of the anchor rod. The anchor rod and the soil column are connected as a whole by utilizing the overall effect of slurry and anchoring sheet, thereby strengthening the stress transfer between the anchor rod and the structure, forming a stable structure, and greatly meeting the reinforcement requirements for the soil column.

[0093] It can be seen from the above embodiments that the method of the present invention can significantly enhance the stability of the tunnel soil columns, has a reasonable reinforcement design, is simple to construct, has high construction efficiency, and has good use effect, and can provide effective, stable, and reliable support for the tunnel.

[0094] The construction method of the present invention avoids the use of advanced horizontal rotary jet grouting piles commonly used in the prior art to reinforce the soil-clamped columns, prevents the impact on the easily damaged areas of the soil-clamped columns, and adopts a new reinforcement method to better ensure the reinforcement of the soil-clamped columns, further enhancing the overall strength of the structure.

[0095] The present invention uses prestressed tension through-anchor rods in combination with grouting to strengthen the anchoring of the internal structure of the soil-clamping column, so that it has better anti-deformation ability and ensures the structural strength of the soil-clamping column; uses a reinforced grid frame to connect the prestressed tension through-anchor rods and the soil-clamping column into a whole, thereby improving the integrity of the structure; the suspended strong steel mesh makes the overall structure of the easily damaged area of ​​the soil-clamping column more solid and the reinforcement effect is better; the sprayed high-performance concrete further strengthens the overall strength of the soil-clamping column.

[0096] The construction method of the present invention adopts the overall coordination of reinforcement grid frame, prestressed tension through anchor rods, grouting, strong steel mesh and high-performance concrete to comprehensively reinforce the entire earth-clamped column, making its overall structural strength more stable, and the construction is simple, safe and fast, which greatly improves and enhances the construction effect, and has significant economic and social effects.

[0097] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for reinforcing soil columns between tunnels, characterized in that: The following steps are involved: (1) According to the construction design requirements, the construction position of the prestressed tension through-bolt is determined on the surface of the soil column formed between the excavated tunnels; (2) Drilling a plurality of through holes according to the above-mentioned construction position, which penetrate the entire thickness of the soil clamping column and are arranged in a matrix in the length and height direction of the soil clamping column; (3) installing the prestressed tension through-anchor rod in the hole, with the two ends of the prestressed tension through-anchor rod protruding from the two surfaces of the soil clamping column respectively; (4) The reinforcement grid frames are respectively installed on the two surfaces of the soil clamping column, and the reinforcement grid frames are respectively sleeved on the ends of the prestressed tension through-anchor rods protruding from the surface of the soil clamping column, and locked by a locking device to fix the reinforcement grid frames on the surface of the soil clamping column; The reinforcement grid frame is welded by a plurality of transverse L-shaped steels and a plurality of longitudinal steel strips, and a through hole is provided at the connection between the L-shaped steel and the steel strip, and the end of the prestressed tension through-anchor protruding from the surface of the soil clamping column passes through the through hole; (5) Strong steel mesh is used to completely cover the two end faces of the soil clamping column, and the two ends of the strong steel mesh are hung on the ends of the corresponding prestressed tension through-anchor rods protruding from the surface of the soil clamping column. One end of the strong steel mesh is also provided with a tension adjustment device to adjust the overall covering force of the strong steel mesh on the end face of the soil clamping column; The strong steel mesh is made by the following steps: 1) Straighten the steel bars, cut them into sections, and remove oxides and dirt from the surface of the steel bars; 2) The steel bar is strongly drawn, placed in a tempering furnace and heated to 550°C for 3.5 hours for tempering. During this process, neon gas is introduced as a protective gas. The drawing-tempering process is repeated three times in succession. After the tempering is completed, the steel bar is cooled by air. Each drawing reduces the diameter of the steel bar by 1 mm. After that, two annealing treatments are performed, each time heating to 480°C, holding for 1 hour, and then cooling at a rate of 20°C / min. 3) Straighten the steel bars for the second time and then weld them to form a strong steel mesh; In the above steps, removing oxides and dirt on the surface of the steel bars means spraying nitric acid onto the steel bars through a high-pressure atomizing nozzle, leaving it at room temperature for 15 minutes, then heating it to 130°C, keeping it at that temperature and leaving it for 10 minutes; then performing ultrasonic cleaning for 10-15 minutes, and then performing drying; The tension adjustment device includes a mounting frame, a plurality of driving cylinders and a tension detection unit; the plurality of driving cylinders are fastened to the mounting frame at uniform intervals in the vertical direction, and the movable ends thereof are respectively connected to the corresponding tensile steel strands, and the other ends of the tensile steel strands are connected to one end of the strong steel mesh, and each tensile steel strand is accommodated in a corresponding guide tube for the convenience of tensile guidance, and the guide tube is arranged on the mounting frame; the tension detection unit includes a pressure sensing unit connected to the driving cylinder, a signal receiver connected to the pressure sensing unit, and a control unit; The specific operation of tensioning the strong steel mesh is as follows: hang one end of the strong steel mesh on the end of the corresponding prestressed tension through-anchor rod protruding from the surface of the soil clamping column, connect the tensile steel strand at the other end, and then connect it to the tensioning adjustment device, and temporarily fix the tensioning adjustment device on the other side surface of the soil clamping column; according to the design requirements, start the tensioning adjustment device to slowly tension the strong steel mesh, and monitor the tensioning process in real time through the tension detection unit; when the expected tensioning force is reached, stop the tensioning adjustment device and maintain the existing tensioning force, and hang the other end of the strong steel mesh on the end of the corresponding prestressed tension through-anchor rod protruding from the surface of the soil clamping column at an appropriate position to keep it in a tensioned state; finally, remove the tensioning adjustment device to complete the tensioning construction; (6) tensioning the prestressed tension through-anchor rods on the surfaces of the soil clamping columns respectively, and locking them after tensioning so that they exert an anchoring force on the soil clamping columns; On one side of the soil clamping column, half of the prestressed tensioned through-anchor rods are tensioned, and at this time, the tensioned prestressed tensioned through-anchor rods are spaced two by two; after the tensioning is completed, the other half of the prestressed tensioned through-anchor rods are tensioned on the other side of the soil clamping column, and at this time, the tensioned prestressed tensioned through-anchor rods are spaced two by two; (7) After the tensioning is completed, high-performance concrete is sprayed on the two surfaces and end faces of the soil-clamping column to completely cover the reinforcement grid frame, the ends of the prestressed tensioning through-anchor rods protruding from the surface of the soil-clamping column, and the strong steel mesh, forming a flat concrete appearance; When the thickness of the soil-binding column is ≤1.2W, the thickness of the sprayed high-performance concrete is 25-30cm, and the thickness of the reinforced grid frame is 10-15cm; when 1.2W<the thickness of the soil-binding column<2W, the thickness of the sprayed high-performance concrete is 20-22cm, and the thickness of the reinforced grid frame is 5-8cm; wherein W is the width of the excavation section of the single-hole tunnel.

2. The method for reinforcing soil columns between tunnels according to claim 1, characterized in that: In step (1), the surface refers to the surface of the soil clamping column facing the inner space of the tunnel; in step (5), the end surface refers to the surface of the soil clamping column that is flush with the tunnel entrance.

3. The method for reinforcing soil columns between tunnels according to claim 2, characterized in that: In step (2), the axial spacing between each of the plurality of through holes is equal.

4. The method for reinforcing soil columns between tunnels according to claim 3, characterized in that: In step (6), after the tensioning is completed, grouting is injected into the prestressed tension-through anchor rod. After the grouting is completed, a grouting stopper is promptly installed, and then a locking mechanism is installed to lock it. The grouting ratio is: cement: sodium silicate = 2:1.