A shaft excavation support construction method

Abstract

The invention discloses a shaft excavation support construction method, including construction layout, drilling construction, charge detonation, ventilation and smoke exhaust, construction lighting and slag removal processes, wherein the charge detonation is: drawing a blasting circle on the construction ground, determining the arc length between each charge hole according to the expected depth of the shaft, the explosive force of the explosive, the radius of the charge hole and the radius of the blasting circle, and determining each charge hole on the blasting circle according to the arc length between each charge hole; placing explosives in the charge hole and detonating to obtain a blasting ring, installing shaft support in the blasting ring, and completing the casting and reinforcement of the inner wall of the blasting ring away from its axis; and removing the soil layer ring between the blasting ring and the borehole. The invention saves the workload of shaft excavation support construction and improves the construction efficiency by setting a circle of charge holes at a distance around the borehole, blasting to obtain the blasting ring, reinforcing the blasting ring and casting the outer inner wall of the blasting ring as the inner wall of the shaft.

Description

Technical Field

[0001] The invention relates to the technical field of shaft construction, in particular to a shaft excavation support construction method. Background Art

[0002] A vertical shaft is a shaft-shaped pipe with upright cave walls. It is usually used in underground projects such as mines, water conservancy and hydropower projects. It has multiple functions such as air supply and ventilation, lifting ore or waste rock, lifting materials and equipment, transporting personnel, laying pipelines and cables, etc. The cross-sectional shape of a vertical shaft is usually circular or square, and its diameter or side length is determined according to actual needs. During the construction of a vertical shaft, appropriate support measures need to be taken to ensure the stability and safety of the shaft wall.

[0003] The steps of shaft excavation and support construction usually include construction layout, drilling construction, charging and detonation, ventilation and smoke exhaust, construction lighting and slag removal. Specifically, first, the construction drawings are matched with the actual construction situation (construction layout), and then the hole is drilled downward to the required depth (drilling construction). At this time, the diameter of the borehole is small and needs to be expanded. The method adopted is to insert vertical charging holes around the borehole, and place explosives in the charging holes and detonate them, so as to widen the borehole (charging and detonation). At this time, a preliminary shaft is obtained, and the shaft can be reinforced. Before reinforcement, since there is a lot of gun smoke in the shaft due to the blasting, the shaft must be ventilated to make the smoke in the shaft free and have the conditions for construction (ventilation and smoke exhaust). After that, lighting can be installed in the shaft so that it can be safely operated underground (construction lighting). Finally, the waste slag generated by the construction is cleared out of the shaft (slag removal), thereby completing the shaft excavation and support construction.

[0004] In this process, charge detonation is a very important step. In the specific implementation, holes are usually drilled around the borehole 1. The holes drilled are called charge holes 2. The charge holes 2 are set at least two circles around the borehole 1. Figure 1As shown, explosives are then placed in the charge hole 2 and detonated, completing one blast. After that, the blasted area needs to be ventilated. After the ventilation is completed, the second blast can be carried out. Generally, due to the deep depth of the shaft, which generally reaches a depth of one or two hundred meters, when blasting, blasting is carried out in sections, such as once every ten meters. Therefore, if blasting is carried out at one time, because there are a large number of blasting holes around the borehole 1 (the charge holes 2 are respectively around the borehole 1 and the number is large, if explosives are placed according to the depth of the shaft, there will be too much explosives and produce huge power), it is easy to cause the shaft to collapse. Although this method is effective and traditional, it is very time-consuming during construction and requires a large number of repeated blasting and clearing, which greatly affects the progress of the project. At the same time, at each blasting, the charge pipe needs to be reinstalled and calibrated, which is time-consuming and labor-intensive, and the construction efficiency is extremely low. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a shaft excavation support construction method in view of the deficiencies in the above-mentioned prior art. When the explosive is detonated, a circle of charging holes is set at a distance around the borehole, and a blasting ring is obtained after blasting. The blasting ring is reinforced by support measures and the outer inner wall of the blasting ring is cast as the inner wall of the shaft, and the soil pile between the inner wall of the shaft and the borehole is shoveled and cleared, thereby saving the workload of the shaft excavation support construction and improving the construction efficiency.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a shaft excavation support construction method, comprising the following steps:

[0007] Step 1: Construction layout

[0008] Determine the location of shaft excavation and support construction according to the construction drawings;

[0009] Step 2: Drilling

[0010] According to the location of the shaft excavation support construction, a drilling machine is used to drill a hole into the ground to the expected depth of the shaft to obtain a borehole;

[0011] Step 3: Charge and detonate

[0012] Step 3-1: Around the borehole, with the intersection of the axis of the borehole and the construction ground as the center of the circle, determine the radius of the blasting circle according to the expected radius of the shaft, draw the blasting circle on the construction ground, determine the length of the arc between each charging hole according to the expected depth of the shaft, the explosive force of the explosive, the radius of the charging hole and the radius of the blasting circle, determine the position of each charging hole on the blasting circle according to the length of the arc between each charging hole, and use a drilling rig to drill holes underground to the expected depth of the shaft to obtain charging holes;

[0013] Step 3-2: Put explosives in the charge hole and detonate to obtain a blasting ring, clean out the soil residue in the blasting ring, install the shaft support in the blasting ring, and cast and reinforce the inner wall of the blasting ring away from its axis;

[0014] Step 3-3: Remove the soil ring between the blasting ring and the drill hole, and clean out the soil residue;

[0015] Step 4: Ventilation and smoke exhaust

[0016] The air is sent to the bottom of the shaft through the air compressor and the air pressure pipe, forming an upward wind flow to discharge the smoke and gas inside the shaft;

[0017] Step 5: Construction lighting

[0018] Remove the shaft support, reinforce the inner wall of the shaft for a second time, and install lighting tools on the inner wall of the shaft;

[0019] Step 6: Slag removal

[0020] Clean up the soil residues and material residues generated by the shaft excavation and support construction.

[0021] Further, in step 3-1, the arc length is calculated by the following formula:

[0022]

[0023] In the formula, s is the length of the arc, T is the explosive force of the explosive, and r 装药孔 is the radius of the charging hole, K 炸药 is the first coefficient, r 爆破圆 is the radius of the blasting circle, K 井深 is the second coefficient and h is the expected depth of the shaft.

[0024] Furthermore, the value range of the first coefficient is 0.075-0.12; the value range of the second coefficient is 0.0083-0.0125.

[0025] Further, in step 3-2, the installation of shaft support in the blasting ring includes:

[0026] Step 3-2-1: Use a detector to detect the three-dimensional model of the blasting ring along the depth direction of the shaft;

[0027] Step 3-2-2: According to the three-dimensional model, a cylindrical steel mesh is made on the inner wall of the blasting ring away from the axis thereof, and the cylindrical steel mesh is installed in the blasting ring so that the cylindrical steel mesh and the inner wall of the blasting ring away from the axis thereof fit together.

[0028] Furthermore, in step 3-2, the step of pouring and reinforcing the inner wall of the blasting ring away from the axis thereof includes:

[0029] Step 3-2-3: Make a casting guard plate according to the cylindrical steel mesh, and install the casting guard plate in the blasting ring so that the casting guard plate fits the cylindrical steel mesh;

[0030] Step 3-2-4: Cast between the casting guard plate and the inner wall of the blasting ring away from its axis, and remove the casting guard plate after the casting is completed.

[0031] Furthermore, the cross section of the cast guard plate coincides with the blasting circle.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] The present invention provides a shaft excavation support construction method, which improves the detonation of explosive charge. When the explosive charge is detonated, a circle of charge holes is set at a distance around the borehole, and a blasting ring is obtained after blasting. The blasting ring is reinforced by support measures, and the outer inner wall of the blasting ring is cast as the inner wall of the shaft, and the soil pile between the inner wall of the shaft and the borehole is shoveled and cleared, thereby saving the workload of the shaft excavation support construction and improving the construction efficiency.

[0034] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the positional relationship between the drill holes and the charging holes in the current shaft excavation support construction method.

[0036] Figure 2 It is a schematic diagram of the positional relationship between the drilling hole and the charging hole in the vertical shaft excavation support construction method of the present invention.

[0037] Figure 3 It is a schematic diagram of the structure of the unfolded cylindrical steel mesh in the present invention.

[0038] Figure 4 It is a schematic cross-sectional view of the longitudinal structure of the shaft during the vertical shaft excavation and support construction in the present invention.

[0039] Description of reference numerals:

[0040] 1. Drilling hole; 2. Charging hole; 3. Blasting circle; 4. Blasting ring; 5. Soil layer ring; 6. Cylindrical steel mesh; 7. Casting guard plate. DETAILED DESCRIPTION

[0041] like Figure 2-4 As shown, the present invention provides a shaft excavation support construction method, comprising the following steps:

[0042] Step 1: Construction layout

[0043] Determine the location of shaft excavation and support construction according to the construction drawings;

[0044] Step 2: Drilling

[0045] According to the location of the shaft excavation support construction, a drilling machine is used to drill a hole underground to the expected depth of the shaft to obtain a borehole 1;

[0046] Step 3: Charge and detonate

[0047] Step 3-1: If Figure 2 As shown, around the borehole 1, with the intersection of the axis of the borehole 1 and the construction ground as the center, the radius of the blasting circle 3 is determined according to the expected radius of the shaft, the blasting circle 3 is drawn on the construction ground, the arc length between each charge hole 2 is determined according to the expected depth of the shaft, the explosive force of the explosive, the radius of the charge hole 2 and the radius of the blasting circle 3, the position of each charge hole 2 is determined on the blasting circle 3 according to the arc length between each charge hole 2, and a drilling rig is used to drill holes into the ground to the expected depth of the shaft to obtain the charge hole 2;

[0048] Step 3-2: Put explosives in the charge hole 2 and detonate to obtain a blasting ring 4, clean out the soil residue in the blasting ring 4, install a shaft support in the blasting ring 4, and complete the pouring and reinforcement of the inner wall of the blasting ring 4 away from its axis;

[0049] Step 3-3: remove the soil ring 5 between the blasting ring 4 and the borehole 1, and clean out the soil residue;

[0050] Step 4: Ventilation and smoke exhaust

[0051] The air is sent to the bottom of the shaft through the air compressor and the air pressure pipe, forming an upward wind flow to discharge the smoke and gas inside the shaft;

[0052] Step 5: Construction lighting

[0053] Remove the shaft support, reinforce the inner wall of the shaft for a second time, and install lighting tools on the inner wall of the shaft;

[0054] Step 6: Slag removal

[0055] Clean up the soil residues and material residues generated by the shaft excavation and support construction.

[0056] The above six steps are several steps of shaft excavation and support construction, and after completion, a usable shaft is obtained. Among them, steps one, two, four, five, and six are not the focus of the present invention, and the improvement focus of the present invention is step three. The charge detonation in step three is also the most important part in the shaft excavation and support construction. This part is the most labor-consuming and time-consuming. The purpose of the present invention is to improve this part and save construction time.

[0057] The present invention improves the traditional method by using a one-time detonation, so that the overall vertical shaft takes shape. After the shaft wall is reinforced, the soil layer ring 5 therein is pushed down, so that the vertical shaft is basically completed.

[0058] From the perspective of construction processes and steps, the processes of the present invention are significantly reduced compared to the existing traditional methods, thereby reducing the construction processes and increasing construction efficiency.

[0059] When the charge is detonated, in order to prevent the shaft from collapsing, the position of the charge hole 2 on the blasting ring 3 needs to be calculated, so that the minimum amount of explosives can be used to complete the construction process, which is also for engineering cost saving.

[0060] In step 3-1, the arc length is calculated using the following formula:

[0061]

[0062] In the formula, s is the length of the arc, T is the explosive force of the explosive, and r 装药孔 is the radius of charging hole 2, K 炸药 is the first coefficient, r 爆破圆 is the radius of the blasting circle 3, K 井深 is the second coefficient and h is the expected depth of the shaft.

[0063] The first coefficient has a value range of 0.075-0.12, and the second coefficient has a value range of 0.0083-0.0125. The first coefficient and the second coefficient are values ​​obtained based on construction experience and tests.

[0064] In the present invention, since the outer wall is obtained at one time by using explosives, it can be used as the blasting ring 4 inside the shaft. At this time, since the geology is still soil or rock, the structure is not very safe. If you are not careful during construction and there is excessive construction, it will easily cause the collapse of the shaft. Therefore, the present invention will reinforce the blasting ring 4 and repair the inner wall of the shaft at the same time.

[0065] When the present invention is implemented, the diameter of the vertical shaft to be constructed is greater than 6 meters, that is, the radius is 3 meters. Generally, the diameter of the charging hole 2 is 10-20 centimeters, and after blasting, the difference between the inner and outer diameters of the blasting ring 4 is about 0.5-1 meter, and the difference between the inner and outer diameters of the soil pile layer is about 2 meters. Even if manual operation is required, it is enough to accommodate multiple people. Generally, if it is necessary to go down the well, 3-4 people will be arranged to go down the well for construction, and complete measures will be taken before going down the well to complete the ventilation operation underground to ensure safety before going down the well for construction.

[0066] In step 3-2 of the present invention, the installation of shaft support in the blasting ring 4 includes:

[0067] Step 3-2-1: Use a detector to detect the three-dimensional model of the blasting ring 4 along the depth direction of the shaft;

[0068] Step 3-2-2: According to the three-dimensional model, a cylindrical steel mesh 6 is made on the inner wall of the blasting ring 4 away from the axis thereof, such as Figure 3 As shown, the cylindrical steel mesh 6 is installed in the blasting ring 4 so that the cylindrical steel mesh 6 and the inner wall of the blasting ring 4 away from its axis are in contact with each other, as shown in FIG. Figure 4 shown.

[0069] After the installation of the above-mentioned cylindrical steel mesh 6 is completed, the following steps can be carried out to reinforce the shaft. The cylindrical steel mesh 6 of the present invention is customized according to the conditions of the shaft, just like the support template.

[0070] That is, in step 3-2, the pouring and reinforcement of the inner wall of the bursting ring 4 away from its axis is completed, including:

[0071] Step 3-2-3: Make a casting guard plate 7 according to the cylindrical steel mesh 6, and install the casting guard plate 7 in the blasting ring 4 so that the casting guard plate 7 fits the cylindrical steel mesh 6;

[0072] Step 3-2-4: Cast between the casting guard plate 7 and the inner wall of the blasting ring 4 away from its axis, and remove the casting guard plate 7 after the casting is completed.

[0073] The cross section of the casting guard plate 7 coincides with the blasting circle 3. In this way, a formed shaft can be obtained at one time. Since the inner wall of the shaft is cast with cement, the integrated cement solidifies the inner wall of the shaft, thus playing a good supporting role for the excavation support of the shaft.

[0074] In summary, the present invention provides a shaft excavation support construction method, which improves the detonation of explosives. When the explosives are detonated, a circle of charging holes is set at a distance around the borehole, and a blasting ring is obtained after blasting. The blasting ring is reinforced by support measures and the outer inner wall of the blasting ring is cast as the inner wall of the shaft, and the soil pile between the inner wall of the shaft and the borehole is shoveled and cleared, thereby saving the workload of the shaft excavation support construction and improving the construction efficiency.

[0075] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A shaft excavation support construction method, characterized in that: The method comprises the following steps: Step 1: Construction layout Determine the location of shaft excavation and support construction according to the construction drawings; Step 2: Drilling According to the location of the shaft excavation support construction, a drilling machine is used to drill a hole underground to the expected depth of the shaft to obtain a borehole (1); Step 3: Charge and detonate Step 3-1: Around the borehole (1), with the intersection of the axis of the borehole (1) and the construction ground as the center, determine the radius of the blasting circle (3) according to the expected radius of the shaft, draw the blasting circle (3) on the construction ground, determine the length of the arc between each charging hole (2) according to the expected depth of the shaft, the explosive force of the explosive, the radius of the charging hole (2) and the radius of the blasting circle (3), determine the position of each charging hole (2) on the blasting circle (3) according to the length of the arc between each charging hole (2), and use a drilling rig to drill a hole into the ground to the expected depth of the shaft to obtain the charging hole (2); In step 3-1, the arc length is calculated using the following formula: In the formula, s is the length of the arc, T is the explosive force of the explosive, and r 装药孔 is the radius of the charge hole (2), K 炸药 is the first coefficient, r 爆破圆 is the radius of the blasting circle (3), K 井深 is the second coefficient, h is the expected depth of the shaft; Step 3-2: placing explosives in the charge hole (2) and detonating them to obtain a blasting ring (4), cleaning out soil residues in the blasting ring (4), installing a shaft support in the blasting ring (4), and completing the pouring and reinforcement of the inner wall of the blasting ring (4) away from its axis; Step 3-3: Shovel out the soil ring (5) between the blasting ring (4) and the drill hole (1) to remove the soil residue; Step 4: Ventilation and smoke exhaust The air is sent to the bottom of the shaft through the air compressor and the air pressure pipe, forming an upward wind flow to discharge the smoke and gas inside the shaft; Step 5: Construction lighting Remove the shaft support, reinforce the inner wall of the shaft for a second time, and install lighting tools on the inner wall of the shaft; Step 6: Slag removal Clean up the soil residues and material residues generated by the shaft excavation and support construction.

2. A shaft excavation support construction method according to claim 1, characterized in that: The value range of the first coefficient is 0.075-0.12; the value range of the second coefficient is 0.0083-0.0125.

3. A shaft excavation support construction method according to claim 1, characterized in that: In step 3-2, the installation of shaft support in the blasting ring (4) comprises: Step 3-2-1: Use a detector to detect the three-dimensional model of the blasting ring (4) along the depth direction of the shaft; Step 3-2-2: According to the three-dimensional model, a cylindrical steel mesh (6) is made on the inner wall of the blasting ring (4) away from its axis, and the cylindrical steel mesh (6) is installed in the blasting ring (4) so ​​that the cylindrical steel mesh (6) and the inner wall of the blasting ring (4) away from its axis fit together.

4. A shaft excavation support construction method according to claim 3, characterized in that: In step 3-2, the process of pouring and reinforcing the inner wall of the bursting ring (4) away from its axis includes: Step 3-2-3: making a casting guard plate (7) according to the cylindrical steel mesh (6), and installing the casting guard plate (7) in the blasting ring (4) so ​​that the casting guard plate (7) fits the cylindrical steel mesh (6); Step 3-2-4: Casting is performed between the casting guard plate (7) and the inner wall of the bursting ring (4) away from its axis, and the casting guard plate (7) is removed after the casting is completed.

5. A shaft excavation support construction method according to claim 4, characterized in that: The cross section of the casting guard plate (7) coincides with the blasting circle (3).

Images