A large-scale karst cave treatment and tunnel excavation method with deep dredging and full filling

Abstract

A method for treating a large fully filled karst cave provided with a deep cave body and excavating a tunnel adopts a three-step seven-procedure method comprising steps of karst cave treatment, pre-grouting, excavation of an upper arc-shaped pilot tunnel, excavation of a middle step, excavation of a lower step and excavation of three steps in the middle. Construction space is large, mechanized construction is convenient, parallel operation on multiple working faces can be realized, and the working efficiency is high; construction procedures can be transformed flexibly and timely, and the construction method can be adjusted; the method is applicable to different spans and various section forms, and primary support procedures are convenient to operate; core soil is reserved on the basis of excavation with the step method, left and right staggered excavation is performed, and stability of excavation working faces is facilitated; when surrounding rock has larger deformation or abrupt change, the closure time can be adjusted as quickly as possible on the premise that safety is guaranteed and a clearance requirement is met, the method is widely applicable to karst cave stratums with special geological conditions, and construction and tunnel safety is guaranteed through rapid, safe and effective tunnel excavation construction under the geological conditions.

Description

technical field [0001] The invention relates to the field of tunnel construction, in particular to a method for treating karst caves and excavating large karst caves when tunnel excavation encounters deep dredging and full filling of large karst caves. Background technique [0002] The formation of caves is the result of long-term dissolution of groundwater in limestone areas. The insoluble calcium carbonate in limestone can be converted into slightly soluble calcium bicarbonate by the action of water and carbon dioxide. This geological phenomenon will affect the stability and mechanical distribution of surrounding rock, and affect the quality of surrounding engineering construction. [0003] In engineering construction, some construction techniques have a great influence on the stress distribution of surrounding rocks. Unavoidable karst caves are encountered, unsafe and unstable factors of engineering structures increase, construction techniques become complicated, and the ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a large-scale karst cave treatment and tunnel excavation method with deep dredging and full filling. It is necessary to solve the problems of long construction time when existing tunnels pass through karst caves, which is not conducive to timely adjustment of closing time and inconvenient machinery. Technical problems of frequent conversion of construction and construction procedures

Images