阅读说明：本技术 一种使隧道安全通过浅埋河沟软弱围岩的方法 (Method for enabling tunnel to safely pass through shallow-buried ditch soft surrounding rock ) 是由 张馨 孙金山 梅红波 郭创科 赵志涛 于国锋 于 2020-05-15 设计创作，主要内容包括：本发明公开了一种使隧道安全通过浅埋河沟软弱围岩的方法,包括以下步骤：(1)在浅埋软弱围岩上方的小溪的上游筑坝堵住溪水,并设置排水管,用防渗混凝土在小溪的底部铺砌；(2)在防渗混凝土上沿隧道长度方向设置若干根地表钢管,沿每根所述地表钢管设置若干组穿过所述浅埋软弱围岩的钻孔,在每组钻孔中的一个钻孔穿设钢绞线,(3)待所有所述钢绞线均锁牢后,用混凝土将所有所述钻孔灌注满,并捣固密实；(4)在隧道内拱部设置超前中管棚和超前小导管,并对所述超前小导管注浆；(5)按照隧道建设方向依次循环步骤(1)-(4),直至隧道通过所述浅埋软弱围岩。本发明提高了隧道通过浅埋软弱围岩时施工的安全性。(The invention discloses a method for enabling a tunnel to safely pass through shallow-buried ditch weak surrounding rocks, which comprises the following steps: (1) building a dam at the upstream of the brook above the shallow-buried weak surrounding rock to block the brook, arranging a drain pipe, and paving the brook at the bottom of the brook by using impermeable concrete; (2) arranging a plurality of surface steel pipes on the impermeable concrete along the length direction of the tunnel, arranging a plurality of groups of drill holes which penetrate through the shallow-buried weak surrounding rock along each surface steel pipe, and penetrating steel strands through one drill hole in each group of drill holes, (3) filling all the drill holes with concrete after all the steel strands are locked firmly, and tamping and compacting; (4) arranging an advanced middle pipe shed and an advanced small guide pipe at an inner arch part of the tunnel, and grouting the advanced small guide pipe; (5) and (5) sequentially circulating the steps (1) to (4) according to the tunnel construction direction until the tunnel passes through the shallow-buried weak surrounding rock. The invention improves the construction safety when the tunnel passes through shallow-buried weak surrounding rocks.)

1. A method for making a tunnel safely pass through shallow-buried ditch weak surrounding rocks is characterized by comprising the following steps:

(1) building a dam at the upstream of the brook above the shallow-buried weak surrounding rock to block the brook, arranging a drain pipe, paving the brook at the bottom by using impermeable concrete, and arranging a steel pipe groove on the impermeable concrete;

(2) arranging a plurality of surface steel pipes on the impermeable concrete along the length direction of the tunnel, arranging a plurality of groups of drill holes which penetrate through the shallow weak surrounding rock along each surface steel pipe, wherein each group of drill holes comprises two drill holes which are respectively positioned at two sides of the surface steel pipe, penetrating a steel strand through one drill hole in each group of drill holes, penetrating the steel strand to the tunnel, penetrating a steel arch frame and a middle pipe shed, penetrating the steel strand through the other drill hole in the same group of drill holes, and binding two ends of the steel strand together;

(3) after all the steel strands are locked firmly, filling all the drill holes with concrete, and tamping to be compact;

(4) arranging an advanced middle pipe shed and an advanced small guide pipe at an inner arch part of the tunnel, and grouting the advanced small guide pipe;

(5) and (5) sequentially circulating the steps (1) to (4) according to the tunnel construction direction until the tunnel passes through the shallow-buried weak surrounding rock.

2. The method of securing a tunnel through shallow trench weak surrounding rock as claimed in claim 1, wherein: in the step (2), before the steel strand is threaded in the drill hole, an auxiliary pipe is firstly threaded in the drill hole, the bottom end of the auxiliary pipe reaches the top end of the tunnel, then the steel strand penetrates through the auxiliary pipe, and after the steel strand is threaded, the auxiliary pipe is pulled out.

3. The method of securing a tunnel through shallow trench weak surrounding rock as claimed in claim 1, wherein: and (4) excavating only one arch truss in the tunnel in each circulation of the steps (1) to (4).

4. The method of securing a tunnel through shallow trench weak surrounding rock as claimed in claim 1, wherein: in the tunnel, construction is divided into three steps, namely an upper step, a middle step and a lower step

5. The method of securing a tunnel through shallow trench weak surrounding rock as claimed in claim 1, wherein: after excavating 1 truss on the upper step, erecting an arch frame, arranging a lock pin anchor pipe on the wall, firmly welding the arch frame with U-shaped steel bars, spraying concrete with the strength grade of C30 of 200mm, and grouting and reinforcing the outside of the arch pin and the lock pin anchor pipe.

6. The method of securing a tunnel through shallow trench weak surrounding rock as claimed in claim 1, wherein: the middle step and the lower step are respectively excavated for 2 trusses, an arch frame is erected, anchor pipes with the diameter of 42mm and the length of 4.0m are arranged on the wall part, the anchor pipes are firmly welded with the arch frame by U-shaped steel bars, and the spraying strength grade is C30 concrete for 200 mm.

Technical Field

The invention relates to the technical field of tunnel engineering, in particular to a method for enabling a tunnel to safely pass through shallow-buried ditch weak surrounding rocks.

Background

When the tunnel needs to penetrate shallow-buried weak surrounding rocks, particularly when the shallow-buried weak surrounding rocks have streams, due to the complex tunnel geological condition, the sandy shale is mixed with vertical bar-shaped calcite veins which are thin layers and chippings and softened into mud when meeting water. At present, the traditional method is to pass through a Vb composite lining, and a middle pipe shed and steel arch support mode passes through the above terrains, but practice proves that the Vb composite lining, the middle pipe shed and steel arch support mode is easy to cause arch distortion and deformation in construction, the primary support is wholly settled and converged, phenomena such as primary support limit invasion and arch collapse are caused, the construction progress is slow, the cost is suddenly increased, and the safety risk is high.

Disclosure of Invention

The invention aims to provide a method for enabling a tunnel to safely pass through shallow-buried soft surrounding rocks of a ditch, so as to solve the problems in the prior art and improve the construction safety when the tunnel passes through the shallow-buried soft surrounding rocks.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a method for enabling a tunnel to safely pass through shallow-buried ditch weak surrounding rocks, which comprises the following steps:

(1) building a dam at the upstream of the brook above the shallow-buried weak surrounding rock to block the brook, arranging a drain pipe, paving the brook at the bottom by using impermeable concrete, and arranging a steel pipe groove on the impermeable concrete;

(2) arranging a plurality of surface steel pipes on the impermeable concrete along the length direction of the tunnel, arranging a plurality of groups of drill holes which penetrate through the shallow weak surrounding rock along each surface steel pipe, wherein each group of drill holes comprises two drill holes which are respectively positioned at two sides of the surface steel pipe, penetrating a steel strand through one drill hole in each group of drill holes, penetrating the steel strand to the tunnel, penetrating a steel arch frame and a middle pipe shed, penetrating the steel strand through the other drill hole in the same group of drill holes, and binding two ends of the steel strand together;

(3) after all the steel strands are locked firmly, filling all the drill holes with concrete, and tamping to be compact;

(4) arranging an advanced middle pipe shed and an advanced small guide pipe at an inner arch part of the tunnel, and grouting the advanced small guide pipe;

(5) and (5) sequentially circulating the steps (1) to (4) according to the tunnel construction direction until the tunnel passes through the shallow-buried weak surrounding rock.

Preferably, in the step (2), before the steel strand is threaded in the bore hole, an auxiliary pipe is first threaded in the bore hole, the bottom end of the auxiliary pipe reaches the top end of the tunnel, then the steel strand is threaded through the auxiliary pipe, and after the steel strand is threaded, the auxiliary pipe is pulled out.

Preferably, only one arch is excavated in the tunnel in each circulation of the steps (1) to (4).

Preferably, in the tunnel, construction is divided into three steps, namely an upper step, a middle step and a lower step

Preferably, after 1 truss is excavated in the upper step, an arch center is erected, a locking anchor pipe is arranged at the wall part, the arch center is firmly welded by U-shaped steel bars, the spraying strength grade is C30 concrete 200mm, and then grouting reinforcement is carried out on the outside of the arch center and the locking anchor pipe.

Preferably, the middle step and the lower step are respectively excavated for 2 trusses, an arch is erected, anchor pipes with the diameter of 42mm and the length of 4.0m are arranged on the wall, the anchor pipes are firmly welded with the arch through U-shaped steel bars, and the spraying strength grade is C30 concrete 200 mm.

Compared with the prior art, the invention has the following technical effects:

the method for enabling the tunnel to safely pass through the shallow-buried soft surrounding rock of the river channel has the advantages of simple and rapid operation and convenient construction, can effectively reduce the construction risk, quickens the construction progress, and improves the construction safety when the tunnel passes through the shallow-buried soft surrounding rock. The method for enabling the tunnel to safely pass through the shallow-buried ditch soft surrounding rock suspends the arch frame and the middle pipe shed by the ground surface long rope, so that the primary support and the surrounding rock form a firm consolidation ring, the primary support is effectively prevented from settling and deforming, and the primary support is prevented from being limited or collapsed. The method ensures that the tunnel can safely exert the effect of the steel wire rope by using the waste steel strand through the method of shallowly burying the soft surrounding rock of the river channel, has low cost, is difficult to rust and elongate and has good use effect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a first schematic structural diagram of the method for making a tunnel safely pass through weak surrounding rocks of a shallow-buried river ditch according to the invention;

FIG. 2 is a schematic structural diagram II of the method for making a tunnel safely pass through weak surrounding rocks of a shallow-buried river ditch according to the invention;

wherein: 1-ground steel pipe, 2-advanced middle pipe shed, 3-steel strand, 4-locking anchor pipe, 5-steel arch frame, 6-inverted arch, 7-inverted arch filling, 8-secondary lining and 9-sling locking joint.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

The invention aims to provide a method for enabling a tunnel to safely pass through shallow-buried soft surrounding rocks of a ditch, so as to solve the problems in the prior art and improve the construction safety when the tunnel passes through the shallow-buried soft surrounding rocks.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1 to 2: the embodiment provides a method for enabling a tunnel to safely pass through shallow-buried ditch weak surrounding rocks, which comprises the following steps:

(1) building a dam at the upstream of the brook above the shallow-buried weak surrounding rock to block the brook, arranging a drain pipe, paving the brook at the bottom by using impermeable concrete, and arranging a steel pipe groove on the impermeable concrete;

(2) arranging a plurality of earth surface steel pipes 1 on the impermeable concrete along the length direction of the tunnel, arranging a plurality of groups of drill holes penetrating through the shallow soft surrounding rock along each earth surface steel pipe 1, wherein each group of drill holes comprises two drill holes respectively positioned at two sides of the earth surface steel pipe 1, penetrating a steel strand 3 through one drill hole in each group of drill holes, penetrating the underground to the tunnel, penetrating a steel arch frame 5 and a middle pipe shed, penetrating the steel strand 3 through the other drill hole in the same group of drill holes, binding two ends of the steel strand 3 together, and arranging sling locking joints 9 on the steel strand 3;

in this embodiment, in order to facilitate the threading of the steel strand 3, before the steel strand 3 is threaded in the borehole, the auxiliary pipe is first threaded in the borehole, and the bottom end of the auxiliary pipe reaches the top end of the tunnel, and then the steel strand 3 passes through the auxiliary pipe, and after the steel strand 3 is threaded, the auxiliary pipe is pulled out.

(3) After all the steel strands 3 are locked firmly, filling all the drill holes with concrete, and tamping to be compact;

(4) arranging an advanced middle pipe shed 2 and an advanced small pipe at an inner arch part of the tunnel, and grouting the advanced small pipe;

(5) and (5) sequentially circulating the steps (1) to (4) according to the tunnel construction direction until the tunnel passes through the shallow-buried weak surrounding rock. And (4) excavating only one arch truss in the tunnel in each circulation of the steps (1) to (4).

In the tunnel, construction is divided into three steps, namely an upper step, a middle step and a lower step

After excavating 1 truss on the upper step, erecting an arch frame, arranging a lock pin anchor pipe 4 on the wall part, firmly welding the arch frame with U-shaped steel bars, spraying concrete with the strength grade of C30 of 200mm, and then grouting and reinforcing the outside of the arch pin and the lock pin anchor pipe 4.

The middle step and the lower step are respectively excavated for 2 trusses, an arch frame is erected, anchor pipes with the diameter of 42mm and the length of 4.0m are arranged on the wall part, the anchor pipes are firmly welded with the arch frame by U-shaped steel bars, and the spraying strength grade is C30 concrete for 200 mm.

And after 3-5 m of primary support, performing primary support back radial grouting by using sulphoaluminate cement to reinforce the primary support and the weak rock stratum behind the primary support. An inverted arch 6 and an inverted arch filling 7 are arranged, and a secondary lining 8 follows closely to the maximum extent. After the primary support and the secondary lining are completely excavated in the shallow buried section, the ground steel strand 3 can be cut off, and the steel pipe can be detached. And paving the bottom of the brook with concrete to recover the normal running water of the brook.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.