Three-connected-arch tunnel double-side cavity construction method for soft geological

Abstract

The invention relates to the technical field for the engineering of large-section tunnel, in particular to an engineering method for the double lateral tunnel of a three-arc tunnel on soft and weak geological condition, which resolves the problem of longer duration for the exposure of wall rock, easy deformation of tunnel and poor waterproof effect in existing tunnel engineering method. The invention comprises: (1) excavation of lateral tunnel; (2) lining of later tunnel: first of all, dismantle the primary support of the whole section, then pour the arc invert secondary lining and arc section secondary lining with the construction joint being configured at the lower section of the middle wall for the lateral tunnel; (3) after the circular lining a left lateral tunnel I and a right lateral tunnel II on a same section, excavate and line a middle tunnel III. This method realizes simple equipment and convenient engineering; with the construction sequence of building the lateral tunnel and then the middle tunnel, the invention gives full play to the supporting function of the secondary lining of the middle wall, so as to reduce the load borne by the primary support of the arc section of middle tunnel and elevate the safety coefficient; the invention reduces the settlement and impact on peripheral environment, so as to ensure the stability and safety of the excavation working face; small number of construction joint and high working efficiency.

Description

technical field [0001] The invention relates to the technical field of large-section tunnel construction, in particular to a double-side hole construction method for a triple-arch tunnel with weak geological conditions. Background technique [0002] At present, under the geological conditions of weak surrounding rock (surrounding rock below Grade IV), the construction of subway underground excavation sections, stations, and other large-section tunnels with triple arches as the secondary lining usually adopts the double-side-wall pilot pit method and the middle-hole method. , Pillar hole method, wherein the double side wall pilot pit method has the following problems in actual construction: (1) block excavation, single block excavation area is large, it is not easy to support in time, the surrounding rock is exposed for a long time, and the excavation face Unstable; (2) When removing the temporary support, it is necessary to increase the reverse support, which weakens the sup...

AI Technical Summary

Problems solved by technology

[0003] The present invention solves the problem of large excavation area of ​​a single block, long exposure time of surrounding rock, easy deformation and cracking of the tunnel, poor support effect, many construction joints and poor waterproof effect when the existing tunnel construction method is used for a large-section tunnel with weak surrounding rock. To provide a new construction method for double-sided tunnels of triple-arch tunnels in weak geology

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