长大隧道穿越断层破碎带的施工方案研究

Research on Construction Plan for Long Tunnel Crossing Fault and Fragmented Zone

由于地质断层破碎带具有岩石破碎、强度低、透水性强、易被风化、剥蚀和搬运的特性,隧道在穿越断层破碎带施工过程中,岩体的稳定性较难把控,易发生隧道地质灾害(坍塌、突水涌泥、大变形)。因此,如何实现隧道断层破碎带的地质和水文情况的提前预判断尤为重要,制定出针对性较强的施工技术措施,确保隧道断层破碎带地段安全有效的施工,是本文研究的目的。本文主要依托云南高速公路网丘北至砚山高速公路特长隧道-冲革隧道穿越地质断层破碎带的施工方案,即采用预留核心土的三台阶七步法开挖围岩、超前注浆、小导管结合型钢加强的方法组织施工,施工过程中以超前地质预报为先导、以监控量测的数据结果作为依据,来制定相应的技术处理措施。本文对长大隧道穿越顺利穿越富水破碎断裂带,总结出一套切实可行的施工工艺及方法,节约了成本,为今后类似施工提供借鉴经验。

Due to the characteristics of rock fragmentation,low strength,strong permeability,and susceptibility to weathering,erosion,and transportation in geological fault fracture zones,it is difficult to control the stability of the rock mass during tunnel construction through fault fracture zones,which can easily lead to geological disasters such as collapse,water and mud inrush,and large deformation.Therefore,it is particularly important to achieve early prediction of the geological and hydrological conditions of tunnel fault zones,and to develop targeted construction technical measures to ensure safe and effective construction in tunnel fault zones.This is the purpose of this study.This article mainly relies on the construction plan of the Chongge Tunnel,a special long tunnel of the Yunnan Expressway network from Qiubei to Yanshan,which crosses the geological fault fracture zone.The construction is organized by using the three-step seven step method of excavating the surrounding rock with reserved core soil,advanced grouting,and small conduits combined with steel reinforcement.During the construction process,advanced geological prediction is taken as the guide and monitoring data results are used as the basis to formulate corresponding technical treatment measures.This article summarizes a set of practical and feasible construction techniques and methods for the smooth crossing of a long tunnel through the rich water fracture zone,which saves costs and provides reference experience for similar construction in the future.