Ice deposit rock roadway tunneling supporting method

Abstract

The invention belongs to the technical field of mining, and particularly discloses an icy rock roadway tunneling and supporting method which comprises the following steps: firstly, performing preparatory work, performing all-directional investigation on a construction area, preparing construction materials and equipment, completing installation and debugging of the equipment in advance, then performing drilling and blasting work, and finally performing drilling and blasting; and then concrete is sprayed on the cross section of the roadway, and anchor rod supporting and steel arch mounting work is conducted after solidification. In order to solve the problem that drilling drifting and hole collapse frequently occur during drilling construction in the roadway tunneling process in an alpine region at present, the temperature of an icy rock construction site is accurately controlled to be below zero DEG C by utilizing a unique low-temperature climate condition, so that the rock stratum strength is greatly improved, the impermeability is remarkably enhanced, and the construction period is shortened. Therefore, the problems that during drilling construction in the roadway tunneling process, drilling drifting, hole collapse and other conditions frequently occur, explosive charging is difficult and heavy, the roadway forming quality is poor, and the tunneling efficiency is low are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of mining, and in particular to a method for supporting glacial rock tunnel excavation. Background Art

[0002] Mine tunneling technology involves excavating underground space to create passageways or chambers. It's a fundamental activity necessary for the exploration and exploitation of mineral deposits. Tunneling can be categorized by location as vertical, horizontal, and inclined. This technology is not only a key foundational technology in underground engineering, but its scope and applications are also expanding with industrial development, with widespread application in mining, water conservancy, transportation, and national defense. Safety and environmental protection measures during tunneling operations are crucial, directly impacting the safety of both workers and the surrounding environment.

[0003] Alpine regions are characterized by high altitudes, perennially low temperatures, and permafrost beneath the soil. Their unique climatic and geographical conditions present numerous challenges for mining operations. This high altitude creates a cold and unpredictable climate in mining areas, with frequent rain and snow. The annual maximum temperature is only around 16°C, occurring only sporadically in July and August. From December to January, temperatures plummet to around -30°C, with extreme low temperatures commonplace. These conditions create significant challenges for both personnel and equipment operation, resulting in difficult working conditions and excessive labor intensity. In glacial permafrost zones, the surrounding rock is primarily composed of residual slope deposits, Quaternary modern glacial deposits, residual slope deposits, ice-water deposits, and glacial deposits such as gravel. This results in severely fragmented surrounding rock. During drilling, drill drift and hole collapse are common, making charging difficult, resulting in poor tunnel formation quality and low excavation efficiency.

[0004] Therefore, it is necessary to design a support method for glacial rock tunneling that fully utilizes the unique low-temperature climate conditions of the region and precisely controls the temperature at the glacial rock construction site to below zero degrees Celsius, significantly increasing the strength of the rock formation and significantly enhancing its impermeability. This avoids frequent drill hole drift and hole collapse during drilling, which lead to difficulties in charging explosives, resulting in poor tunnel formation quality and low tunneling efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a glacial rock tunnel excavation support method to solve the problems of frequent drilling drift, hole collapse, etc. during drilling construction in the tunnel excavation process, which leads to difficulties in charging, and thus causes poor tunnel forming quality and low excavation efficiency.

[0006] To achieve the above-mentioned object, the present invention provides a basic solution: a method for supporting glacial rock tunnel excavation, comprising the following steps: S1: Preparation: Use geological exploration equipment to conduct a comprehensive survey of the construction area, accurately determine the distribution range, thickness variation, rock formation direction and dip geological parameters of the glacial rocks, and draw a geological map. Then, prepare construction materials and equipment according to construction requirements, and complete equipment installation and commissioning on site in advance. Then, hang thermometers on the surface and construction face to monitor temperature changes on site in real time. S2: Drilling and blasting: Use a drilling rig with a 40mm straight drill bit and a hollow hexagonal drill rod to drill several blast holes in the current tunnel section. After drilling is completed, the blasting parameters are determined based on the number of blast holes, blast hole layout, charge amount, and blasting sequence, and blasting is carried out; S3: Support: First, concrete is sprayed on the tunnel section. After the concrete solidifies, anchor support is carried out. After the anchor support is completed, steel arch frames are made and installed according to the tunnel section; S4: Excavation: After the support is completed, the excavation of the current tunnel section is carried out. If the current tunnel section is the last section, the next tunnel section is drilled and blasted.

[0007] The beneficial effects of the present invention are as follows: (1) the present invention utilizes the unique low-temperature climate conditions to precisely control the temperature at the glacial rock construction site to below zero degrees Celsius, thereby greatly improving the strength of the rock layer and significantly enhancing its impermeability, thereby avoiding the frequent occurrence of drill drift and hole collapse during drilling construction; (2) the use of sprayed concrete, anchor rods, and steel arch grouting combined support technology has formed a strict and efficient support system. The various support links work closely together, greatly improving the overall bearing capacity of the broken rock layer, effectively preventing the fall of the tunnel surrounding rock, and ensuring the safety of construction personnel.

[0008] Option 2 is the preferred option of the basic option. In S2, the blasting uses No. 2 rock emulsion explosive, the explosive roll diameter is 32 mm, the explosive roll length is 200 mm, and the explosive roll mass is 150±10 g; No. 2 rock emulsion explosive has excellent detonation performance, strong water resistance, less gun smoke and low toxicity.

[0009] Option three is the preferred basic option. In S3, when spraying concrete, the nozzle is kept perpendicular to the sprayed surface and the distance between the nozzle and the sprayed surface is 80cm-120cm. The water-cement ratio of the concrete is 0.4-0.45. Keeping the nozzle perpendicular to the sprayed surface during concrete spraying can reduce the rebound rate. Maintaining the water-cement ratio of the concrete at 0.4-0.45 can make the surface of the sprayed concrete smooth, moist and shiny, with good visco-plasticity and density. It can effectively avoid problems such as dry spots on the sprayed layer surface, increased rebound rate, and dust flying due to insufficient water. At the same time, it can also avoid concrete slippage and flow caused by excessive water.

[0010] Option 4 is the preferred basic option. In S3, the working wind pressure during spraying concrete is 0.15MPa-0.18MPa, and the spraying thickness is: 50mm-100mm for straight walls and 30mm-60mm for arch walls; stable working wind pressure can ensure that the concrete is evenly and densely attached to the working surface.

[0011] Option 5 is the preferred basic option. When spraying concrete, the working wind pressure increases by 0.08MPa-0.1MPa for every 100m increase in horizontal feeding; the working wind pressure increases by 0.02MPa-0.03MPa for every 10m increase in vertical feeding, and the water pressure is 0.1MPa higher than the working wind pressure; the working wind pressure at the injection outlet is guaranteed to be stable, thereby ensuring that the concrete is evenly and densely attached to the working surface. The water pressure is always maintained at about 0.1MPa higher than the working wind pressure, which can effectively prevent dry materials from clogging the nozzle, ensure that the concrete mixture is fully moistened and evenly sprayed, and at the same time enhance the adhesion and density of the concrete.

[0012] Option 6, which is the preferred basic option, in S3, the steps of anchor support are: Step 1: First, based on the anchoring force distribution characteristics of anchor bolts in relatively broken glacial rock layers, that is, the anchoring force is distributed at a 45-degree angle from the bottom and end of the anchor bolt, the anchor net support parameters are designed; Step 2: Then start hanging the net from the junction of the bottom plate and the vertical wall. The overlap of the anchor net is 10cm, and the spacing between rows is 1m×1m; Step 3: After the mesh is hung, the tunnel with mesh support is sprayed with concrete for the second time every 10m.

[0013] The anchoring effect of the anchor rod can effectively combine the surrounding rock fragments, thereby improving the overall stability of the rock formation, delaying the destruction process of the surrounding rock, and providing a guarantee for the long-term stability of the tunnel.

[0014] Option seven is the preferred basic option. In step two, when anchor support is performed, the angle between the anchor and the joint surface is greater than 80°, which can fully exert the anchoring effect of the anchor.

[0015] Option 8, which is the preferred basic option, in S3, the steps for installing the steel arch are: A: First, clear the obstacles in the roadway where the steel arch frame will be installed, and then use a measuring instrument to determine the center line, elevation, and arch foot design position of the steel arch frame installation; B: Before installing the steel arch frame, check the installation parameters. After ensuring that they are correct, thoroughly clean the slag and debris at the column foot, and then install and fix the column foot; C: After the column base is fixed, the arch frame is installed from bottom to top, and the longitudinal connecting beam is welded after the installation is completed; D: Then use 140mm hot-rolled channel steel to lay vertical and horizontal supports every 10m-15m, then lay 4mm steel plates on top of the steel arch frame, and finally pour concrete for the steel arch frame.

[0016] The steel arch frame itself not only has a high bearing capacity, but can also evenly disperse the surrounding rock pressure through close fit with the surrounding rock and the coordinated action of vertical supports, horizontal supports and connecting beams, effectively improving the adaptability and reliability of the support structure.

[0017] Option nine is the preferred basic option. In option B, when the column foot height is insufficient, steel plates or poured concrete are used to adjust it so that the two column feet are located on the same straight line. Adjusting the column foot height using steel plates or poured concrete can improve the overall stability of the steel arch frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a site view after construction is completed in a glacial rock tunnel excavation support method of the present invention; Figure 2 This is a simulated stress distribution diagram of the tunnel surrounding rock after anchor support is performed in a glacial rock tunnel excavation support method of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below through specific embodiments: Example A method for supporting glacial rock tunnel excavation, such as Figure 1 and Figure 2 The following steps are shown: S1: When starting the support work for glacial rock tunneling, the first step is to carry out preparatory work: use geological exploration equipment to conduct a comprehensive survey of the construction area, accurately determine the distribution range, thickness changes, rock formation direction and inclination geological parameters of the glacial rock, and draw a geological map; then prepare construction materials and equipment according to construction needs, and complete the installation and commissioning of equipment on site in advance. Then, hang thermometers on the surface and construction face to monitor the temperature changes on site in real time.

[0020] S2: Then the drilling and blasting work is carried out: First, use the Epiroc 291 drilling rig with a 40mm straight drill bit and a hollow hexagonal drill rod to open several blast holes in the current tunnel section. Then load the blast holes with No. 2 rock emulsion explosives. The explosive roll has a diameter of 32mm, a length of 200mm, and a mass of 150±10g. It is detonated with a 6m foot line digital electronic detonator.

[0021] S3: Then proceed with tunnel support work: First, spray concrete on the tunnel section, with the nozzle perpendicular to the sprayed surface and the distance between the nozzle and the sprayed surface being 80cm-120cm. The water-cement ratio of the concrete is 0.4-0.45, and the working air pressure is 0.15MPa-0.18MPa. During spraying, the working air pressure increases by 0.08MPa-0.1MPa for every 100m increase in horizontal feed; and by 0. 02MPa-0.03MPa, the water pressure is always 0.1MPa higher than the working wind pressure, the spraying thickness is: 50mm-100mm for the vertical wall and 30mm-60mm for the arch wall; then after the concrete solidifies, anchor support is carried out. First, according to the distribution characteristics of the anchor force of the anchor in the broken glacial rock layer, which is distributed at a 45° angle from the bottom and end of the anchor, the anchor net support parameters are designed. Then, the net is hung from the joint of the bottom plate and the vertical wall, and the anchor is fixed. The overlap of the net is 10cm, and the spacing between rows is 1m×1m. After the net is hung, the tunnel with the net support is sprayed with concrete for the second time every 10m. After the anchor support is completed, the steel arch frame is made and installed according to the tunnel section. First, the obstacles in the tunnel where the steel arch frame is installed are cleared, and then the center waistline, elevation and arch foot design position of the steel arch frame installation are determined using a measuring instrument. Then the installation parameters of the steel arch frame are checked. After ensuring that there are no errors, the slag and debris at the column foot are thoroughly cleaned, and then the column foot is installed and fixed. If the column foot height is insufficient, the height is adjusted by using steel plates or pouring concrete so that the two column feet are in the same straight line. After the column foot is fixed, the arch frame is installed from bottom to top. After the installation is completed, the longitudinal connecting beam is welded, and then 140mm hot-rolled channel steel is used to lay vertical and horizontal supports every 10m-15m. Then 4mm steel plates are laid on top of the steel arch frame, and finally the steel arch frame concrete is poured.

[0022] S4: Excavation: After the support is completed, the excavation of the current tunnel section will be carried out. If the current tunnel section is the last section, drilling and blasting work will be carried out on the next tunnel section.

[0023] In summary, the above method, utilizing the unique low-temperature climate conditions in the high-altitude cold region, precisely controls the temperature at the glacial rock construction site to below 0°C, significantly increasing the rock strength and significantly enhancing its impermeability. This avoids frequent drill drift and hole collapse during drilling, which can lead to difficulties in charging explosives, resulting in poor tunnel formation quality and low excavation efficiency. By employing a combined support system of shotcrete, anchor rods, and steel arch grouting, a rigorous and efficient support system has been formed. The close coordination of various support links has greatly improved the overall bearing capacity of the broken rock strata, effectively preventing the collapse of the surrounding rock in the tunnel and ensuring the safety of construction workers.

[0024] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for supporting glacial rock tunnel excavation, characterized in that: The following steps are involved: S1: Preparation: Use geological exploration equipment to conduct a comprehensive survey of the construction area, accurately determine the distribution range, thickness variation, rock formation direction and dip geological parameters of the glacial rocks, and draw a geological map. Then, prepare construction materials and equipment according to construction requirements, and complete equipment installation and commissioning on site in advance. Then, hang thermometers on the surface and construction face to monitor temperature changes on site in real time. S2: Drilling and blasting: Use a drilling rig with a 40mm straight drill bit and a hollow hexagonal drill rod to drill several blast holes in the current tunnel section. After drilling is completed, the blasting parameters are determined based on the number of blast holes, blast hole layout, charge amount, and blasting sequence, and blasting is carried out; S3: Support: First, concrete is sprayed on the tunnel section. After the concrete solidifies, anchor support is carried out. After the anchor support is completed, steel arch frames are made and installed according to the tunnel section; S4: Excavation: After the support is completed, the excavation of the current tunnel section is carried out. If the current tunnel section is the last section, the next tunnel section is drilled and blasted.

2. A method for supporting glacial rock tunnel excavation according to claim 1, characterized in that: In S2, the blasting uses No. 2 rock emulsion explosive, the explosive roll diameter is 32 mm, the roll length is 200 mm, and the roll mass is 150±10 g.

3. The method for supporting glacial rock tunnel excavation according to claim 1, characterized in that: In S3, when spraying concrete, the nozzle is kept vertical to the sprayed surface and the distance between the nozzle and the sprayed surface is 80cm-120cm, and the water-cement ratio of the concrete is 0.4-0.

45.

4. The method for supporting glacial rock tunnel excavation according to claim 1, characterized in that: In S3, the working wind pressure during shotcrete spraying is 0.15MPa-0.18MPa, and the spraying thickness is: 50mm-100mm for straight walls and 30mm-60mm for arch walls.

5. A method for supporting glacial rock tunnel excavation according to claim 4, characterized in that: When spraying concrete, the working wind pressure increases by 0.08MPa-0.1MPa for every 100m increase in horizontal conveying; the working wind pressure increases by 0.02MPa-0.03MPa for every 10m increase in vertical conveying, and the water pressure is 0.1MPa greater than the working wind pressure.

6. The method for supporting glacial rock tunnel excavation according to claim 1, characterized in that: In S3, the steps of anchor support are: Step 1: First, based on the anchoring force distribution characteristics of anchor bolts in relatively broken glacial rock layers, that is, the anchoring force is distributed at a 45-degree angle from the bottom and end of the anchor bolt, the anchor net support parameters are designed; Step 2: Then start hanging the net from the junction of the bottom plate and the vertical wall. The overlap of the anchor net is 10cm, and the spacing between rows is 1m×1m; Step 3: After the mesh is hung, the tunnel with mesh support is sprayed with concrete for the second time every 10m.

7. A method for supporting glacial rock tunnel excavation according to claim 6, characterized in that: In step 2, when anchor support is performed, the angle between the anchor and the joint surface is greater than 80°.

8. The method for supporting glacial rock tunnel excavation according to claim 1, characterized in that: In S3, the steps for installing the steel arch are: A: First, clear the obstacles in the roadway where the steel arch frame will be installed, and then use a measuring instrument to determine the center line, elevation, and arch foot design position of the steel arch frame installation; B: Before installing the steel arch frame, check the installation parameters. After ensuring that they are correct, thoroughly clean the slag and debris at the column foot, and then install and fix the column foot; C: After the column base is fixed, the arch frame is installed from bottom to top, and the longitudinal connecting beam is welded after the installation is completed; D: Then use 140mm hot-rolled channel steel to lay vertical and horizontal supports every 10m-15m, then lay 4mm steel plates on top of the steel arch frame, and finally pour concrete for the steel arch frame.

9. A method for supporting glacial rock tunnel excavation according to claim 8, characterized in that: In B, when the column base height is insufficient, steel plates or poured concrete are used to adjust it so that the two sides of the column base are located on the same straight line.

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