WO2021088349A1

WO2021088349A1 - Method for excavating tunnel shaft

Info

Publication number: WO2021088349A1
Application number: PCT/CN2020/090406
Authority: WO
Inventors: 徐强; 何开伟; 李强
Original assignee: 中铁二局集团有限公司; 中铁二局第四工程有限公司
Priority date: 2019-11-08
Filing date: 2020-05-15
Publication date: 2021-05-14
Also published as: CN110821497A

Abstract

A method for excavating a tunnel shaft (1), by drilling a number of holes I (2) with smaller diameters, it is possible to predict groundwater and bad geology etc. in advance, which is convenient for confirming the degree of coincidence of the geological survey data, so as to provide guidance for subsequent construction and reduce construction risks and difficulties, at the same time, the excavation from top to bottom does not require the restriction of the formation of a positive hole at the bottom of the shaft (1), it can also be constructed in a non-blasting manner, which has high safety and can loosen the rock and soil in advance, improves the construction efficiency of excavation, and shortens the construction period.

Description

Method for excavating tunnel shaft

Technical field

The invention relates to the technical field of tunnels and underground engineering, in particular to a method for excavating a tunnel shaft.

Background technique

At present, in underground engineering at home and abroad, such as water conservancy and hydropower engineering, coal engineering, petroleum engineering, highway and railway long tunnel traffic engineering, subway engineering, etc., shaft construction is very common. According to the different construction conditions, the construction methods are also different. Excavation can be carried out by the upwell method and the upwell drilling rig method. According to the geological conditions and groundwater conditions, the excavation can be carried out after the enclosure structure and water stop measures are taken in advance.

The main shaft method is mainly suitable for construction under the condition that there is no passage at the bottom of the shaft, that is, the flat hole at the bottom of the shaft has not been formed, and the shaft needs to be formed first. The main construction method is to use the umbrella drill to drill first, artificial charging, smooth blasting, and then use The rock grabbing machine loads the blasting slag into the bucket and the winch lifts it to the ground. However, due to the use of blasting technology, it is not suitable for construction sites with complex surrounding environments such as urban areas and schools; the raise-drilling construction method is mainly suitable for the formation of the shaft bottom Under the conditions of construction, the main construction method is to use raise drilling rigs (or directional drilling rigs) to carry out pilot hole (generally 270mm diameter) construction from top to bottom. After the pilot hole is opened, install the drill reaming bit at the bottom of the shaft, and then down Reaming upwards to form a pilot well (generally 1400mm in diameter). After the pilot well is penetrated, it is manually expanded from bottom to top to form a slag chute, and the slag excavated by the reaming is directly slipped from the slag chute to the flat hole at the bottom of the well. Inside, the slag truck transports the slag directly in the Pingdong.

At present, when there is no passage at the bottom of the shaft, most of the various shaft constructions adopt the main shaft excavation technology of mechanical and blasting, and the application of non-blasting excavation construction technology is less.

Summary of the invention

The purpose of the present invention is to overcome the prior art in the urban tunnel construction, it is not suitable to use the blasting method to excavate, if there is no channel at the bottom, the non-blasting method of excavating the construction efficiency is low, and the excavation process is deep for a long time. Under the pit operation, the safety risk period is long, the safety risk is high and the above-mentioned shortcomings, provide a tunnel shaft excavation method.

In order to achieve the above objectives, the present invention provides the following technical solutions:

A method for excavating a tunnel shaft includes the following steps:

a. Stake out the center position of the positioning shaft, mark the excavation range of the shaft according to the positioning center point, and then construct reinforced concrete locks and ground beams at the head of the shaft;

b. Mark a number of holes to be excavated in the range of the shaft to be excavated, and there is a gap between two adjacent holes, and then excavate all the holes in the order of the periphery first and then the center. In the first hole, excavate all the holes at the same time and excavate the partition holes. After each hole is excavated to the bottom, the drilling slag mixed with cement is backfilled into the corresponding hole one, and then the next hole is excavated. One of said holes;

c. After the last hole one is backfilled, perform a secondary excavation within the excavation range of the shaft and break the walls between two adjacent holes one and between the hole one and the shaft wall The shaft is supported while digging, and the excavation of the shaft is completed after all the supporting work is completed;

Wherein, the number and distribution of the first hole are determined according to the diameter of the first drill bit and the diameter of the shaft. The first drill bit is used to drill the first hole, and the diameter of the first hole is smaller than the diameter of the shaft.

First set out and locate, mark the excavation range of the shaft, and construct the lock and ground beam at the wellhead, and then dig a number of holes in the range to be excavated in the shaft. The diameter of the hole 1 depends on the diameter of the drill bit 1. According to the diameter of the first hole and the diameter of the shaft, determine the number and distribution of the first hole, excavate from the periphery to the middle, and excavate the hole during the excavation, that is, the next hole one is excavated and the previous one At least one hole one is spaced between one hole one, and each hole one is backfilled as soon as the excavation is completed. After all the hole one is backfilled, the excavation range of the shaft is opened for a second time. During excavation, excavation is carried out in layers, and the excavation is carried out while supporting until the excavation of the shaft is completed. By using this method to drill several holes with smaller diameters, the groundwater and bad geological conditions can be predicted in advance It is convenient to verify the degree of coincidence of the geological survey data, so as to provide guidance for subsequent construction and reduce construction risks and difficulties. At the same time, excavation from top to bottom is used, without the restriction of forming a positive hole at the bottom of the shaft, and non-blasting can also be used. Formal construction, high safety, and can drill loose rock and soil in advance, improve the construction efficiency of excavation, shorten the construction period, especially shorten the operation time of artificial deep foundation pit, effectively reduce safety risks, save construction costs, and have a wide range of promotion significance.

Preferably, in the step b, one hole one is spaced between the next hole one to be excavated and the previous hole one.

Preferably, in the step c, the specific steps are as follows:

c1. First excavate one side area of the shaft and break the wall in the corresponding range, and the excavation depth is 50-60cm;

c2. Then excavate the other side area of the shaft and destroy the wall in the corresponding range, and the excavation depth is the same as the excavation depth in step c1;

c3. Clean up the muck within the corresponding depth;

c4. Support the shaft wall at the corresponding depth of the shaft;

c5. Repeat steps c1-c4 until the support of the shaft is completed.

Using the method of re-excavating and supporting after backfilling greatly reduces the idle time of the drill bit for excavating hole one, ensures the effective use of the drill bit, and relatively lowers the drilling cost.

Preferably, in the step b, the mass of the mixed cement is 5%-8% of the mass of the drill slag.

Preferably, the interval between two adjacent holes is 10-20 cm.

Preferably, the first hole is drilled by the rotary drill.

In summary, compared with the prior art, the beneficial effects of the present invention are:

1. Using the tunnel shaft excavation method of the present invention, by now drilling several holes with smaller diameters, it is possible to predict the conditions of groundwater and bad geology in advance, and it is convenient to confirm the degree of coincidence of the geological prospecting data, so as to Subsequent construction provides guidance to reduce construction risks and difficulties. At the same time, it uses top-down excavation without the restriction of forming a hole at the bottom of the shaft. It can also be constructed in a non-blasting manner, which is safe and can be drilled in advance to loosen the rock and soil. The construction efficiency of the excavation is improved, the construction period is shortened, especially the operation time of the artificial deep foundation pit is shortened, the safety risk is effectively reduced, and the construction cost is saved, which has a wide range of promotion significance.

2. Adopting a tunnel shaft excavation method of the present invention, using a rotary drill to drill a hole instead of a conventional water mill drill core plus splitting excavation method, creating a large-area empty surface, convenient for construction, and for hard Rock formations are particularly suitable.

3. The use of the tunnel shaft excavation method of the present invention greatly reduces the idle time of the drill bit for excavating hole one, ensures the effective use of the drill bit, and relatively lowers the drilling cost.

Description of the drawings:

Fig. 1 is a flow chart of a method for excavating a tunnel shaft according to the present invention;

Figure 2 is a schematic diagram of step a according to the present invention;

Figure 3 is a schematic diagram of step b according to the present invention;

Figure 4 is the second schematic diagram of step b according to the present invention;

Figure 5 is the third schematic diagram of step b according to the present invention;

Figure 6 is a fourth schematic diagram of step b according to the present invention;

Figure 7 is a schematic diagram five of step b according to the present invention;

Fig. 8 is a schematic diagram of step c according to the present invention.

Mark in the picture: 1-shaft, 2-hole one.

Detailed ways

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. However, it should not be understood that the scope of the above-mentioned subject of the present invention is limited to the following embodiments, and all technologies implemented based on the content of the present invention belong to the scope of the present invention.

Example 1

As shown in Figure 1, the method for excavating a tunnel shaft according to the present invention includes the following steps:

a. Loft the center position of the positioning shaft 1, mark the excavation range of the shaft 1 according to the positioning center point, and then construct reinforced concrete locks and ground beams at the head of the shaft 1;

b. Mark the range to be excavated for a number of holes-2 in the range of the shaft 1 to be excavated, and there is an interval between the two adjacent holes-2, and the interval is 10-20cm, and then use Excavate all the

holes

1 and 2 in the order of the periphery first and then the center. When all the

holes

1 and 2 are excavated, excavate the partition holes. After each hole 2 is excavated to the bottom, mix the drilling slag with cement Backfill the corresponding hole-2, and then excavate the next hole-2;

c. After the last hole-2 is backfilled, a secondary excavation is carried out within the excavation range of the shaft 1 and the space between the two adjacent holes-2, the hole-2 and the shaft 1 is broken. The wall between the walls is supported while digging, and the excavation of the shaft 1 is completed after all the supporting work is completed;

Wherein, the number and distribution of the hole-2 are determined according to the diameter of the drill bit one and the diameter of the shaft 1. The drill bit one is used to drill the hole-2, and the diameter of the hole-2 is smaller than the diameter of the shaft 1. The diameter of shaft 1.

Specifically, as shown in Fig. 2, first set out and locate, mark the excavation range of the shaft 1, and construct the lock and the ground beam at the head of the well.

Then, within the range of shaft 1 to be excavated, a rotary drill is used to excavate a number of holes-2. The diameter of the hole-2 depends on the diameter of the drill bit one. According to the diameter of the hole-2 and the diameter of the shaft 1, Determine the number and distribution of the holes-2, and the interval between two adjacent holes-2 is 10-20cm, as in the example of this embodiment, the diameter of the shaft 1 is 6.88m, and the rotary digging The drill bit one has a diameter of 1.5m, that is, the diameter of the hole-2 is 1.5m. The arrangement of all the holes-2 is shown in Figure 3. For ease of description, all the holes in Figure 3 2 is numbered, there are 14 holes-2 in total, distributed in two circles, ①#-⑩#hole-2 is located in the outer ring,

#-

#孔一2 is located in the inner circle. During excavation, the excavation is separated from the periphery to the middle. There is at least one hole one between the next hole-2 and the previous hole-2. 2. As shown in Figure 4-7, the excavation sequence is ①#-③#-⑤#-⑦#-⑨#-②#-④#-⑥#-⑧#-⑩#-

#-

#, you can also start with any serial number of hole-2, such as from ③#, ⑦#, then you can also excavate in a counterclockwise direction, or you can excavate with multiple holes-2, such as ①#-④ #-⑥#-⑧#, after the construction of all the holes 1-2 of the outer ring is completed, the construction of the holes 1-2 of the inner ring can be carried out. The inner ring can also be excavated from any hole 1-2, and then continue to separate. Hole excavation of the next hole-2, each hole-2 will be backfilled after the excavation is completed, that is, the next hole-2 will be excavated after the backfilling is completed, and the backfill will be mixed with 5%- 8% cement is backfilled.

After all the

holes

1 and 2 are backfilled, the excavation range of the shaft 1 is excavated twice, and the excavation is carried out in layers during excavation, and the excavation is carried out while supporting until the shaft 1 is completed. Excavation, specifically, first excavate the area on one side of the shaft 1, such as park the excavator on the left area of the shaft 1 in Fig. 7, excavate the right area of the shaft 1 in Fig. 7, and open When digging, firstly start excavation from the part of the hole-2 in the corresponding area, and at the same time break the wall in the corresponding range, that is, the space between the two holes-2 and the hole-2 The distance between the excavation depth and the edge of the shaft 1 is 50-60 cm. After opening the corresponding elevation, the excavator moves to the right area of the shaft 1 in Fig. 7 and excavates the left side of the shaft 1 in Fig. 7 In the side area, when the left area is also dug to the corresponding elevation, the excavator is used to remove the slag. After the removal is completed, the excavator is lifted out of the shaft 1, and the shaft wall of the corresponding depth of the shaft 1 is carried out. Supporting, after completing the corresponding supporting work, hoist the excavator into the shaft 1 to excavate the next layer, repeat the steps of excavating the excavator, and then excavate 50-60cm and support, Until the final completion of the excavation work of the tunnel shaft 1.

By using this method to drill several holes with smaller diameters, it can predict groundwater and bad geology in advance, and it is convenient to confirm the degree of coincidence of the geological survey data, so as to provide guidance for subsequent construction and reduce construction risks and difficulties. At the same time, use Excavation from the top to the bottom, without the restriction of the formation of the main hole at the bottom of the shaft, it can also be constructed in the form of non-blasting, which has high safety and can be drilled in advance to loosen the rock and soil, which improves the construction efficiency of excavation and shortens the construction period, especially It shortens the operation time of artificial deep foundation pits, effectively reduces safety risks, saves construction costs, and has extensive promotion significance.

The above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

A method for excavating a tunnel shaft is characterized in that it comprises the following steps:

a. Stake out the center position of the positioning shaft (1), mark the excavation range of the shaft (1) according to the positioning center point, and then construct reinforced concrete locks and ground beams at the head of the shaft (1);

b. Mark a number of holes one (2) to be excavated in the range of the shaft (1) to be excavated, and there is a gap between two adjacent holes (2), and then use the first periphery Excavate all the holes one (2) in sequence in the rear center, and excavate all the holes one (2) when excavating all the holes one (2), and after excavating to the bottom of each hole one (2), drill The slag mixed cement is backfilled back into the corresponding hole one (2), and then the next hole one (2) is excavated;

c. After the last hole (2) is backfilled, perform a secondary excavation within the excavation range of the shaft (1) and break the gap between two adjacent holes (2) and the The wall between the hole one (2) and the wall of the shaft (1) is supported while digging, and the excavation of the shaft (1) is completed after all the supporting work is completed;

Wherein, the number and distribution of the first hole (2) are determined according to the diameter of the first drill bit and the diameter of the shaft (1). The first drill bit is used to drill the first hole (2), and the first hole is used to drill the first hole (2). The diameter of (2) is smaller than the diameter of the shaft (1).
The method according to claim 1, characterized in that, in the step b, the next hole one (2) to be excavated and the previous hole one (2) are separated by one hole one. (2).
The method according to claim 1, wherein in the step c, the specific steps are as follows:

c1. First excavate one side area of the shaft (1) and destroy the wall in the corresponding range, and the excavation depth is 50-60cm;

c2. Then excavate the other side area of the shaft (1) and destroy the wall in the corresponding range, and the excavation depth is the same as the excavation depth in step c1;

c3. Clean up the muck within the corresponding depth;

c4. Support the shaft wall at the corresponding depth of the shaft (1);

c5. Repeat steps c1-c4 until the support of the shaft (1) is completed.
The method according to any one of claims 1 to 3, characterized in that, in the step b, the mass of the cement mixed is 5%-8% of the mass of the drill slag.
The method according to any one of claims 1-3, wherein the interval between two adjacent holes (2) is 10-20 cm.
The method according to any one of claims 1 to 3, wherein the hole one (2) is drilled by the rotary drill.