Construction method suitable for dumped rock mass slope water delivery port excavation

Abstract

The invention belongs to the technical field of tunnel construction, and particularly discloses a construction method suitable for dumped rock mass slope water delivery port excavation, which comprises the following steps: determining the position of a water delivery port of a water delivery tunnel to be excavated in a dumped rock mass slope; determining a rock plug extending to the water conveyance tunnel based on the position; after the water delivery tunnel is excavated to one end of the rock plug, a temporary tunnel bypassing the rock plug is excavated, and the end point of the temporary tunnel is located at the other end of the rock plug; excavating and supporting the slope of the toppled rock mass; and after the dumped rock mass slope is excavated and supported, excavation is conducted from the two ends of the rock plug to the middle, and excavation construction of the water delivery tunnel is completed. According to the method, the stability of the water delivery opening of the water delivery tunnel is greatly protected in the modes of rock plug reserving and temporary tunnel bypass construction, meanwhile, bidirectional construction can be conducted on the rock plug, the construction progress requirements of excavation of the water delivery tunnel and a toppling rock mass slope are met, and the construction period is not affected.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction and discloses a construction method suitable for excavating a water delivery outlet on a slope of a dumped rock mass. Background Art

[0002] During traditional water tunnel excavation, when the water inlet is located on the slope of the inverted rock mass, the water is usually directly excavated according to the water tunnel line. This method can easily lead to instability of the water tunnel excavation. At the same time, the subsequent excavation of the inverted rock mass slope at the water inlet will also affect the water inlet, which is very detrimental to project safety and construction schedule. Summary of the Invention

[0003] The purpose of the present invention is to provide a construction method suitable for excavating a water outlet on a collapsed rock mass slope, so as to solve the technical problem that the water outlet of a water tunnel excavated on a collapsed rock mass slope easily leads to instability of the water tunnel.

[0004] The present invention provides a construction method suitable for excavating a water outlet on a slope of a dumped rock mass, comprising: Determine the location of the water outlet of the planned water tunnel in the slope of the dumped rock mass.

[0005] A rock plug extending toward the water transfer tunnel is determined based on the location.

[0006] After the water transfer tunnel is excavated to one end of the rock plug, a temporary tunnel is excavated to bypass the rock plug, with the terminus of the temporary tunnel located at the other end of the rock plug; and the slope of the dumped rock mass is excavated and supported.

[0007] After the excavation and support of the dumped rock mass slope are completed, excavation is carried out from both ends of the rock plug toward the middle to complete the excavation construction of the water diversion tunnel.

[0008] Preferably, the excavation and support of the dumped rock mass slope are carried out as follows: The dumped rock slope is excavated and supported in stages from top to bottom.

[0009] Preferably, the dumped rock mass slope is excavated and supported in stages from top to bottom, specifically: Step S1, excavating the upper dumping rock slope, and tensioning the upper anchor cable using a preset percentage of the design load; Step S2: excavating the adjacent lower-level dumped rock slope, and tensioning the lower-level anchor cables using a preset percentage of the design load, and compensating tensioning the upper-level anchor cables; Step S3, repeating step S2 until the last level of the dumped rock mass slope is excavated, tensioning the last level of anchor cables using the design load, and compensating tensioning the previous level of anchor cables.

[0010] Preferably, the preset percentage is 65%-75%.

[0011] Preferably, when tensioning the upper and lower anchor cables using a preset percentage of the design load, steel pads are used at the tensioning ends to disperse the loads of the corresponding anchor cables.

[0012] Preferably, after compensating tensioning of the upper anchor cable, the corresponding steel pad is removed, and the tensioned end is fixed with a concrete pier head.

[0013] Preferably, excavation is carried out from both ends of the rock plug toward the middle, specifically: The reserved core soil excavation method is adopted to excavate from both ends of the rock plug toward the middle.

[0014] Preferably, the length of the rock plug is greater than or equal to 3 times the excavation diameter of the water transfer tunnel.

[0015] Preferably, the minimum distance between the rock plug and the excavation slope is greater than or equal to 3 times the excavation diameter of the water diversion tunnel.

[0016] The construction method of the present invention, which is applicable to excavating a water outlet on a slope of a dumped rock mass, has the following beneficial effects compared to the prior art: By pre-storing rock plugs and constructing a temporary tunnel via a detour, this method significantly protects the stability of the water delivery tunnel's water inlet and reduces the potential for tunnel collapse caused by direct tunnel excavation. This method allows for simultaneous construction of the temporary tunnel and the rockfall slope. After the rockfall slope is excavated and supported, the rock plug can be constructed in both directions, meeting the construction schedule requirements for both the water delivery tunnel and the rockfall slope excavation without impacting the construction period.

[0017] The present invention separates the excavation of the dumped rock mass slope and the excavation of the water transfer tunnel by reserving rock plugs, thereby protecting the stability of the water transfer tunnel and the dumped rock mass slope; after the dumped rock mass slope is excavated and supported, the rock plug is excavated by reserving core soil, which can reduce the impact of excavation on the supported excavated slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flowchart of a construction method for excavating a water outlet on a slope of a dumped rock mass according to an embodiment of the present invention.

[0019] Figure 2 Schematic diagram of the structure of the dumped rock slope in an embodiment of the present invention.

[0020] Figure 3 Schematic diagram of the location of the temporary tunnel in an embodiment of the present invention.

[0021] Figure 4The present invention is a process diagram of a construction method for excavating a water outlet on a slope of a dumped rock mass according to an embodiment of the present invention.

[0022] In the figure: 1. Dumped rock slope; 2. Water diversion tunnel; 3. Temporary tunnel; 4. Excavated slope; 5. Access tower; 6. Rock plug; 7. Water diversion outlet. DETAILED DESCRIPTION

[0023] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0024] The embodiment of the present invention provides a construction method suitable for excavating a water outlet on a slope of a dumped rock mass, such as Figures 1 to 4 Shown, including: Step 1: Determine the position of the water inlet 7 (i.e., water inlet or outlet) of the planned water tunnel 2 in the dumped rock mass slope 1.

[0025] Step 2: Based on the position, determine a rock plug 6 extending toward the water tunnel 2. The rock plug 6 can protect the water tunnel 2 from the blasting effect during the subsequent excavation of the rock mass slope 1.

[0026] Step 3: After the water tunnel 2 is excavated to one end of the rock plug 6, a temporary tunnel 3 is excavated to bypass the rock plug 6. The starting point of the temporary tunnel 3 is located at one end of the rock plug 6 in the water tunnel 2, and the end point of the temporary tunnel 3 is located at the other end of the rock plug 6; at the same time, the dumped rock slope 1 is excavated and supported.

[0027] In this embodiment of the present invention, the length of rock plug 6 is greater than or equal to three times the excavation diameter of water tunnel 2, and the minimum distance between rock plug 6 and excavation slope 4 is greater than or equal to three times the excavation diameter of water tunnel 2. The excavation diameter is the diameter of the excavated section of water tunnel 2, and the excavation slope 4 is the inclined surface formed by excavating the tilted rock slope 1.

[0028] The embodiment of the present invention limits the parameters of the above-mentioned two rock plugs 6, so that the rock plugs 6 can play the role of rock pillars, avoiding mutual influence between the water tunnel 2 and the temporary tunnel 3, and between the temporary tunnel 3 and the dumped rock slope 1. At the same time, the rock plugs 6 can also protect the water tunnel 2 from the impact of blasting during the excavation of the dumped rock slope 1, thereby improving the stability of the water tunnel 2.

[0029] The above-mentioned excavation and support of the dumped rock mass slope 1 is specifically: performing graded excavation and graded support on the dumped rock mass slope 1 from top to bottom.

[0030] The above-mentioned graded excavation and graded support of the dumped rock slope 1 from top to bottom are specifically as follows: Step S1: excavate the upper dump rock slope 1 and tension the upper anchor cable using a preset percentage of the design load.

[0031] The graded excavation in the embodiment of the present invention can be specifically performed according to the elevation of the dumped rock mass slope 1 or according to the soil layers in the dumped rock mass slope 1 .

[0032] The preset percentage in the embodiment of the present invention is 65%-75%. For example, it can be 65%, 70%, 75%, etc.

[0033] Step S2: excavate the adjacent lower-level dumped rock slope 1, and tension the lower-level anchor cables using a preset percentage of the design load, and perform compensatory tensioning on the upper-level anchor cables. The preset percentage in step S2 is also 65%-75%.

[0034] The above-mentioned compensatory tensioning of the upper anchor cable specifically involves tensioning the upper anchor cable to the design load.

[0035] Step S3, repeating step S2 until the last level of the dumped rock mass slope 1 is excavated, tensioning the last level of anchor cables using the design load, and compensating tensioning the previous level of anchor cables.

[0036] In this embodiment of the present invention, when tensioning the upper and lower anchor cables at a preset percentage of the design load, steel pads are used at the tensioning end to distribute the load of the corresponding anchor cables. Simultaneously, after compensatory tensioning of the upper anchor cable, the corresponding steel pads are removed, and the tensioning end is secured with a concrete pier.

[0037] The present invention takes into account the influence of blasting and excavation of the lower-level dumped rock slope 1 on the tensioning force of the adjacent upper-level anchor cable. The first tensioning is locked with a temporary steel pad, and the second compensatory tensioning is locked with a concrete pier head, which can ensure that the final tensioning force of the anchor cable meets the design requirements. At the same time, the steel pad can be reused, saving costs while ensuring the effectiveness of the support measures for the dumped rock slope 1.

[0038] Step 4: After the excavation and support of the dumped rock slope 1 are completed, excavation is carried out from both ends of the rock plug 6 toward the middle to complete the excavation construction of the water diversion tunnel 2.

[0039] The excavation is carried out from both ends of the rock plug 6 toward the middle, specifically, excavation is carried out from both ends of the rock plug 6 toward the middle by adopting a reserved core soil excavation method.

[0040] Due to the influence of the dumped rock slope 1, the rock conditions at the water tunnel 2 are poor. Therefore, the embodiment of the present invention adopts the reserved core soil excavation method to excavate the rock plug 6 to protect the excavation slope 4 of the water outlet 7 and the stability of the water tunnel 2.

[0041] In the embodiment of the present invention, after step 4 , an inlet and outlet tower 5 is constructed at the water inlet 7 to control the water flow in the water tunnel 2 .

[0042] The present invention adopts a detour construction method of a temporary tunnel 3 when constructing the water delivery port 7 in the dumped rock slope 1, so that the temporary tunnel 3 and the dumped rock slope 1 can be constructed at the same time, which greatly protects the stability of the water delivery port 7 of the water delivery tunnel 2, reduces the possibility of tunnel collapse caused by direct excavation of the water delivery tunnel 2, and also meets the construction progress requirements of the excavation of the water delivery tunnel 2 and the dumped rock slope 1, without affecting the construction period.

[0043] The present invention separates the excavation of the dumped rock slope 1 and the excavation of the water tunnel 2 by reserving a rock plug 6, thereby protecting the stability of the water tunnel 2 and the dumped rock slope 1; after the excavation and support of the dumped rock slope 1 are completed, the rock plug 6 is excavated by the reserved core soil excavation method, which can reduce the impact of the excavation on the supported excavated slope 4.

[0044] The above descriptions are merely several embodiments of the present invention and do not constitute any form of limitation to the present invention. Although the present invention is disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Any technician familiar with the present profession, without departing from the scope of the technical solution of the present invention, who makes slight changes or modifications using the technical contents disclosed above, is equivalent to an equivalent implementation case and falls within the scope of the technical solution.

Claims

1. A construction method suitable for excavating a water inlet on a slope of a dumped rock mass, characterized in that: include: Determine the location of the water outlet of the proposed water tunnel in the slope of the dumped rock mass; determining a rock plug extending toward the water tunnel based on the location; After the water transfer tunnel is excavated to one end of the rock plug, a temporary tunnel is excavated to bypass the rock plug, with the terminus of the temporary tunnel located at the other end of the rock plug; and the slope of the dumped rock mass is excavated and supported; After the excavation and support of the dumped rock mass slope are completed, excavation is carried out from both ends of the rock plug toward the middle to complete the excavation construction of the water diversion tunnel.

2. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 1, characterized in that: The excavation and support of the dumped rock slope are carried out as follows: The dumped rock slope is excavated and supported in stages from top to bottom.

3. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 2, wherein: The dumped rock slope is excavated and supported in stages from top to bottom, specifically: Step S1, excavating the upper dumping rock slope, and tensioning the upper anchor cable using a preset percentage of the design load; Step S2: excavating the adjacent lower-level dumped rock slope, and tensioning the lower-level anchor cables using a preset percentage of the design load, and compensating tensioning the upper-level anchor cables; Step S3, repeating step S2 until the last level of the dumped rock mass slope is excavated, tensioning the last level of anchor cables using the design load, and compensating tensioning the previous level of anchor cables.

4. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 3, wherein: The preset percentage is 65%-75%.

5. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 3, characterized in that: When tensioning the upper and lower anchor cables using a preset percentage of the design load, steel pads are used at the tensioning ends to disperse the load of the corresponding anchor cables.

6. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 3, characterized in that: After compensating and tensioning the upper anchor cable, the corresponding steel pad is removed and the tensioning end is fixed with a concrete pier head.

7. The construction method for excavating a water inlet for a dumped rock mass slope according to claim 1, characterized in that: Excavation is carried out from both ends of the rock plug toward the middle, specifically: The reserved core soil excavation method is adopted to excavate from both ends of the rock plug toward the middle.

8. The construction method for excavating a water outlet for a dumped rock mass slope according to any one of claims 1 to 7, characterized in that: The length of the rock plug is greater than or equal to 3 times the excavation diameter of the water diversion tunnel.

9. The construction method for excavating a water inlet for a dumped rock mass slope according to any one of claims 1 to 7, characterized in that: The minimum distance between the rock plug and the excavation slope is greater than or equal to 3 times the excavation diameter of the water diversion tunnel.

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