Non-explosion excavation construction method for IV-grade and V-grade surrounding rock stratum small-section tunnel

Abstract

The invention belongs to the technical field of tunnel benching method construction, and particularly relates to a non-explosive excavation construction method for a small-section tunnel in IV-grade and V-grade surrounding rock stratums. A tunnel is tunneled through a step method, upper-layer horizontal auxiliary holes consistent with a tunnel design longitudinal slope are formed in an upper step of the tunnel, vertical auxiliary holes are formed in the middle pull groove portion of a lower step of the tunnel, and lower-layer horizontal auxiliary holes consistent with the tunnel design longitudinal slope are formed in a reserved rock shoulder portion of a side wall of the lower step of the tunnel. After the upper-layer horizontal auxiliary hole, the vertical auxiliary hole and the lower-layer horizontal auxiliary hole are drilled, the tunnel upper step, the groove broaching part in the middle of the tunnel lower step and the reserved rock shoulder part of the side wall of the tunnel lower step are sequentially broken through a breaking machine; according to the IV-grade and V-grade surrounding rock stratum small-section tunnel non-explosion excavation construction method, a conventional mechanical equipment tool is used, a down-the-hole drill is used for punching, a plurality of crushing auxiliary holes are formed, the rock mass is cut, the free face is created, a small machine is assisted in crushing the rock mass, the construction efficiency is improved, and the construction cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel step method construction, and specifically relates to a non-explosive excavation construction method for a small-section tunnel in a IV or V grade surrounding rock stratum. Background Art

[0002] In order to protect the structural safety of existing buildings (structures), urban subways, commercial ancillary tunneling projects, and small-section tunnels (5.0-8.0m wide and 6.0-9.0m high) in rock formations near existing lines and sensitive pipelines, non-explosive excavation construction methods such as expansion agents, drilling and splitting combinations, or mechanical excavation are usually used. The initial support deformation is strictly controlled, and the step method is often used for partial construction. The working surface is narrow, and large hydraulic breakers and rock drills cannot be used. The expansion agent and drilling and splitting combination construction method is usually used in hard rock formations (rock saturated uniaxial compressive strength> 60MPa, integrity index> 0.55, and integrity is relatively complete to complete). The rock strength is high and the rock integrity is good. The effect achieved by the external force splitting principle is good. Small mechanical chiseling is usually used in extremely soft rock to relatively soft rock formations (rock saturated uniaxial compressive strength ≤ 30MPa, integrity index < 0.55, and degree of integrity is extremely broken to relatively broken), where the rock strength is low and the rock integrity is poor, and small hydraulic breaker has a better effect of crushing and excavation. However, for non-explosive excavation of small-section tunnels of Class IV and V surrounding rock (relatively soft rock to relatively hard rock formations, 15MPa < rock saturated uniaxial compressive strength ≤ 60MPa, 0.15 < integrity index < 0.75, and degree of integrity is broken to relatively complete), the use of external force splitting is affected by factors such as poor rock integrity, low rock strength, and strong plasticity, and the splitting effect is often very poor; when using small mechanical chiseling, it is limited by rock strength, the breaking efficiency is low, the construction progress is slow, and the construction cost is often very high. Summary of the invention

[0003] The invention aims to solve the problem of low construction efficiency and high cost of conventional small-section tunnel IV and V grade surrounding rock using non-explosive excavation methods such as expansion agent, drilling and splitting combination and small mechanical chiseling.

[0004] The present invention provides the following technical scheme: a non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock stratum, wherein the tunnel is excavated by a step method, an upper horizontal auxiliary hole consistent with the designed longitudinal slope of the tunnel is drilled in the upper step of the tunnel, a vertical auxiliary hole is drilled in the middle groove portion of the lower step of the tunnel, and a lower horizontal auxiliary hole consistent with the designed longitudinal slope of the tunnel is drilled in the rock shoulder portion reserved in the side wall of the lower step of the tunnel; after the upper horizontal auxiliary hole, the vertical auxiliary hole and the lower horizontal auxiliary hole are drilled, a demolition machine is used to sequentially demolish the upper step of the tunnel, the middle groove portion of the lower step of the tunnel, and the rock shoulder portion reserved in the side wall of the lower step of the tunnel, and support is completed.

[0005] Furthermore, the upper horizontal auxiliary holes are arranged in a plum blossom shape on the face, and the drilling spacing is 400 to 600 mm.

[0006] Furthermore, the vertical auxiliary holes are arranged in a plum blossom shape vertically downward using the upper step working surface, with a drilling spacing of 400 to 600 mm, and the vertical auxiliary holes are drilled once to the height of the tunnel bottom slab excavation line.

[0007] Furthermore, the lower level auxiliary holes are arranged in a rectangular shape on the face of the tunnel, the drilling spacing is 500 to 800 mm, and the length of one drilling is the same as the reserved length of the lower step.

[0008] Furthermore, the diameters of the upper horizontal auxiliary holes, the vertical auxiliary holes and the lower horizontal auxiliary holes are 80 to 150 mm.

[0009] Furthermore, the reserved rock shoulders on the side walls of the lower steps of the tunnel are excavated and supported on the left and right sides at a distance of at least 3m along the mileage direction of the tunnel.

[0010] Furthermore, the upper horizontal auxiliary hole is drilled in a length of 10m at a time.

[0011] Compared with the prior art, the advantages of the present invention are:

[0012] The present invention provides a non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation. Conventional mechanical equipment and tooling are used to drill a plurality of crushing auxiliary holes through a down-the-hole drill to cut the rock mass, create an open surface, and assist small-scale machinery in crushing the rock mass, thereby improving construction efficiency and reducing construction costs. At the same time, the classified implementation of the horizontal auxiliary holes of the upper step, the vertical auxiliary holes of the grooved part in the middle of the lower step, and the horizontal auxiliary holes of the rock shoulders reserved on the side walls of the lower step ensures the construction sequence of the step method and the safety of tunnel excavation support. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the tunnel cross-section diagram;

[0014] Figure 2 This is a cross-section diagram of the tunnel.

[0015] In the figure: 1-upper step of the tunnel; 1.1-upper horizontal auxiliary hole; 2-groove in the middle of the lower step of the tunnel; 2.1-vertical auxiliary hole; 3-reserved rock shoulder on the side wall of the lower step of the tunnel; 3.1-lower horizontal auxiliary hole; 4-breaking machinery. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] like Figure 1 , Figure 2 As shown: a non-explosive excavation construction method for small-section tunnels in grade IV and V surrounding rock strata, which is suitable for small-section tunnels with a width of 5.0-8.0m and a height of 6.0-9.0m. The tunnel is excavated using the step method. An upper horizontal auxiliary hole 1.1 consistent with the designed longitudinal slope of the tunnel is drilled at the upper step 1 of the tunnel, a vertical auxiliary hole 2.1 is drilled at the middle groove position 2 of the lower step of the tunnel, and a lower horizontal auxiliary hole 3.1 consistent with the designed longitudinal slope of the tunnel is drilled at the reserved rock shoulder position 3 of the side wall of the lower step of the tunnel. After the upper horizontal auxiliary hole 1.1, the vertical auxiliary hole 2.1 and the lower horizontal auxiliary hole 3.1 are drilled, a demolition machine 4 is used to sequentially demolish the upper step 1 of the tunnel, the middle groove position 2 of the lower step of the tunnel, and the reserved rock shoulder position 3 of the side wall of the lower step of the tunnel, and the support is completed.

[0018] The step method construction sequence is ensured by the classified implementation of the upper horizontal auxiliary hole 1.1 of the tunnel upper step 1, the vertical auxiliary hole 2.1 of the grooved part 2 in the middle of the tunnel lower step, and the lower horizontal auxiliary hole 3.1 of the reserved rock shoulder part 3 of the tunnel lower step side wall. The tunnel upper step 1 is excavated and supported first, then the grooved part 2 in the middle of the tunnel lower step is constructed, and then the reserved rock shoulder part 3 of the tunnel lower step side wall is constructed. The reserved rock shoulder part 3 of the tunnel lower step side wall is excavated and supported at least 3m away from the left and right sides along the tunnel mileage direction, or alternately excavated and supported on the left and right sides to ensure the initial support stability of the tunnel and construction safety.

[0019] The upper horizontal auxiliary holes 1.1 are arranged in a plum blossom shape on the face of the tunnel, with a drilling spacing of 400 to 600 mm; the upper horizontal auxiliary holes 1.1 are drilled 10 m in length at a time.

[0020] The vertical auxiliary holes 2.1 are arranged in a plum blossom shape vertically downward using the upper step working surface, with a drilling spacing of 400 to 600 mm. The vertical auxiliary holes 2.1 are drilled once to the height of the tunnel bottom slab excavation line.

[0021] The lower level auxiliary holes 3.1 are arranged in a rectangular shape on the face of the tunnel, with a drilling spacing of 500 to 800 mm. The length of one drilling is the same as the reserved length of the lower step, and the length of one drilling is 6 to 8 m.

[0022] The upper horizontal auxiliary hole 1.1, the vertical auxiliary hole 2.1 and the lower horizontal auxiliary hole 3.1 are drilled by conventional crawler-type down-the-hole drilling rigs, and the diameters of the upper horizontal auxiliary hole 1.1, the vertical auxiliary hole 2.1 and the lower horizontal auxiliary hole 3.1 are 80 to 150 mm. The demolition machine 4 is a small crawler excavator.

[0023] Using conventional mechanical equipment and tooling, multiple crushing auxiliary holes are set up through down-the-hole drilling rigs to cut the rock mass, create an open surface, and assist small-scale machinery in crushing the rock mass (softer rock to harder rock formations, 15MPa<rock saturated uniaxial compressive strength ≤60MPa, 0.15<integrity index<0.75, degree of integrity is crushed to relatively intact), which improves construction efficiency and reduces construction costs.

[0024] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation, characterized in that: The tunnel is excavated by the step method. An upper horizontal auxiliary hole (1.1) consistent with the designed longitudinal slope of the tunnel is drilled on the upper step (1) of the tunnel. A vertical auxiliary hole (2.1) is drilled at the middle groove position (2) of the lower step of the tunnel. A lower horizontal auxiliary hole (3.1) consistent with the designed longitudinal slope of the tunnel is drilled at the reserved rock shoulder position (3) of the side wall of the lower step of the tunnel. After the upper horizontal auxiliary hole (1.1), the vertical auxiliary hole (2.1) and the lower horizontal auxiliary hole (3.1) are drilled, a demolition machine (4) is used to sequentially demolish the upper step (1), the middle groove position (2) of the lower step of the tunnel and the reserved rock shoulder position (3) of the side wall of the lower step of the tunnel, and the support is completed.

2. The non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to claim 1, characterized in that: The upper horizontal auxiliary holes (1.1) are arranged in a plum blossom shape on the face of the tunnel, and the drilling spacing is 400-600 mm.

3. The non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to claim 2, characterized in that: The vertical auxiliary holes (2.1) are arranged in a plum blossom shape vertically downward using the upper step working surface, with a drilling interval of 400-600 mm. The vertical auxiliary holes (2.1) are drilled once to the height of the tunnel bottom plate excavation line.

4. The non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to claim 3, characterized in that: The lower level auxiliary holes (3.1) are arranged in a rectangular shape on the face of the tunnel, the drilling spacing is 500-800 mm, and the length of one drilling is the same as the reserved length of the lower step.

5. A non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to any one of claims 1 to 4, characterized in that: The diameters of the upper horizontal auxiliary holes (1.1), the vertical auxiliary holes (2.1) and the lower horizontal auxiliary holes (3.1) are 80 to 150 mm.

6. The non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to claim 1, characterized in that: The reserved rock shoulder area (3) of the side wall of the lower step of the tunnel is excavated and supported at least 3m apart on the left and right sides along the tunnel mileage direction.

7. The non-explosive excavation construction method for a small-section tunnel in a Class IV or V surrounding rock formation according to claim 5, characterized in that: The upper horizontal auxiliary hole (1.1) is drilled for a length of 10m at a time.

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