Diversion tunnel extremely-weak surrounding rock section construction method

A technology for water diversion tunnels with weak surrounding rocks, applied in the field of tunnels, can solve problems such as difficulty in forming rapid closure, difficulty in controlling the setting time, and large diffusion range

Inactive Publication Date: 2019-05-24
SINOHYDRO ENG BUREAU 4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The grouting setting time of the existing common grouting materials is difficult to control, the diffusion range is large

Method used

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  • Diversion tunnel extremely-weak surrounding rock section construction method
  • Diversion tunnel extremely-weak surrounding rock section construction method
  • Diversion tunnel extremely-weak surrounding rock section construction method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Specific engineering application examples of pea gravel backfill grouting provided by the embodiments of the present invention;

[0067] 1) Project overview

[0068] The excavation diameter of the TBM tunnel in this project is 5.48m, the tunnel forming diameter is 4.6m, and the thickness of the segment is 30cm. The gap between the excavated tunnel section and the segment is backfilled with mortar within 90° of the bottom arch, and the rest of the gap is backfilled with pea pebbles grouting.

[0069] During the backfill grouting process, due to the large gap between the segment and the surrounding rock, it is difficult to start the pressure during the grouting process, the backfill grouting cannot be closed normally, and the grouting process cannot be implemented normally, resulting in the grouting being not dense. According to engineering practice, it is planned that every 50m ~ 100m form a closed loop.

[0070] Closed loop implementation steps:

[0071] (1) A specia...

Embodiment 2

[0130] TBM construction includes 5# construction branch tunnel K0+558.3~K+3+535.04 and water conveyance main tunnel T5+580~T16+110 TBM construction tunnel section, using a double shield TBM for construction, 5# construction branch tunnel (TBM access tunnel) length 3535.04m, TBM construction section longitudinal slope -2.365%, excavation length 2976.74m, main tunnel stake number T5+850~T16+110, length 10260m, longitudinal slope 0.1%, of which stake number T5+850~ T10+950 and T12+750~T15+100 are excavated by TBM with a total length of 7.45km. The excavation diameter of the TBM is 5.48m, and the section is circular. Prefabricated C50 and C60 concrete segment linings are used. The inner diameter of the segment lining is 4.6m, the thickness of the segment is 30cm, and the outer diameter of the segment is 5.2m. The 360° range of the void is filled with pea gravel and backfilled with grouting.

[0131] Such as figure 2 As shown, the schematic diagram of the grouting area behind th...

Embodiment 3

[0159] 1), TBM bean gravel backfill grouting construction process:

[0160] (1) Construction process

[0161] Bean gravel backfilling→pointing→closed ring→bottom arch filling quick-setting cement slurry→side arch non-grouting hole sealing→primary grouting→secondary grouting→sealing→checking

[0162] (2) Bean gravel dredging: When the segment is pushed out of the tail shield, the pea gravel on both sides of the segment should be backfilled first, and then the top bean gravel should be backfilled.

[0163] (3) Bottom grouting: to discharge the flowing water (construction water and external water) in the cavity of the partition bottom arch. Construction backfilling and grouting When the bottom arch segments are assembled, use bagged gypsum powder or bagged mortar mixed with dry material to seal. Then do the bottom grouting.

[0164] (iv) Closed ring grouting: set a closed ring every 30-50 meters for pressure grouting grout sealing.

[0165] (5) One-time grouting: After the be...

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Abstract

The invention belongs to the technical field of tunnels and discloses a diversion tunnel extremely-weak surrounding rock section construction method. The method includes: adopting a TBM (tunnel boringmachine) pea gravel backfill grouting method to backfill pea gravel; sealing bottom segment non-grouted holes; after pea gravel backfill of segments, timely cleaning pea gravel in two discharging holes A and I of an inverted arch, and adopting specially-made CK microexpansion mortar to block and trowel the holes; grouting a front portion of a TBM rear match; in the middle of the TBM rear match, using specially-made CK mortar to block non-grouted holes according to a certain hole sequence. A bottom-to-front left-right-symmetry grouting method is adopted for lateral and top arch backfill grouting; after grouting is finished, accumulated water and dirt in holes should be eliminated after initial setting of grout in the holes, and the specially-made CK microexpansion mortar is adopted to block, compact and trowel the holes.

Description

technical field [0001] The invention belongs to the technical field of tunnels, in particular to a construction method for extremely weak surrounding rock sections of water diversion tunnels. Background technique [0002] At present, the existing technologies commonly used in the industry are as follows: [0003] The water source construction project in Lanzhou uses Liujiaxia Reservoir as a source of diversion water to supply water to Lanzhou City. The project includes the water intake, the main tunnel of the water conveyance tunnel, the water diversion well, the Lujiaping water conveyance branch line, the Pengjiaping water conveyance branch line and the flow and pressure regulating station, the Lujiaping water plant and the Pengjiaping water plant, etc. The main tunnel of the water conveyance tunnel has a total length of 31.29km. [0004] The water intake of the project is located in Dongxiang County, Linxia Hui Autonomous Prefecture, on the right bank of the reservoir ab...

Claims

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Application Information

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IPC IPC(8): E21D11/10E21D9/06
Inventor 梁国辉曹建锋周永永张鹏赵东平张自成
Owner SINOHYDRO ENG BUREAU 4
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