中老铁路高地应力软岩隧道施工方法比选分析  

Comparison and analysis of construction methods for high geo-stress soft rock tunnels of China-Laos Railway

作　　者：王春海 Wang Chunhai(China Railway 19th Bureau Group Co.,Ltd.,Shenyang 110200,China)

机构地区：[1]中铁十九局集团有限公司,沈阳110200

出　　处：《工程勘察》2023年第2期1-7,共7页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金(51878572)。

摘　　要：高能场体环境下大变形、岩爆等隧道灾害屡见不鲜,该类环境的主要特征为高地应力,隧道的地应力条件将会影响围岩变形规律和结构内力,开挖工法的选择将直接影响隧道工程的效率和安全。已有研究在工法模拟时的地应力条件大多根据隧道埋深计算,与实际地应力条件相差较大,导致结果过于片面。因此,本文基于地应力实测结果,采用有限差分软件对高地应力软岩隧道情况下三台阶法、CD法、CRD法施工的围岩变形规律及结构安全性进行分析研究,结合工程现场监测结果,验证结论的正确性。分析结果表明:中老铁路高地应力环境表现为水平最大主应力大于竖向最大主应力,二者比值在1.15~1.71之间;CRD法对高地应力软岩环境下围岩变形的控制效果最佳,CD法其次;高地应力软岩环境下二次衬砌轴力整体分布均匀,仰拱和拱脚部位的弯矩较大,安全系数小;CRD法情况下的围岩压力整体最小,对于围岩稳定最有利,CD法次之,三台阶法的围岩压力最大。Tunnel disasters such as the large deformation and rock burst are common in high-energy field environments,and the main feature of such environments is high geo-stress.The geo-stress conditions of tunnel will affect the deformation law of the surrounding rock and the internal force of the structure.The choice of the excavation method will directly affect the efficiency and safety of the tunnel project.Most of the geo-stress conditions in the existing studies are calculated according to the buried depth of the tunnel,which differs significantly from the actual ground stress conditions,resulting in too one-sided results.Therefore,based on the measured results of in-situ stress,the finite difference software is used to simulate the tunnel excavation in the environment of high geo-stress soft rock.The surrounding rock deformation and structural internal force laws of three-step method,CD method and CRD method are studied,and the correctness of the conclusions is verified by combining the on-site monitoring results.The study results show that:the high geo-stress environment of the China-Laos Railway is characterized by a horizontal maximum principal stress greater than the vertical maximum principal stress,with the ratio of the two stresses from 1.15 to 1.71;the CRD method has the best control effect on the deformation of the surrounding rock in the high geo-stress environment,followed by the CD method;under the high geo-stress environment,the axial force of each part of the secondary lining changes little,and the bending moment of the inverted arch and the arch foot is large and the safety factor is small;the surrounding rock pressure from the CRD method is the smallest,which is the most favorable for the stability of the surrounding rock,followed by the CD method,and the three-step method has the largest surrounding rock pressure.

关 键 词：高地应力 施工工法 水压致裂 位移监测 有限差分 

分 类 号：TU45[建筑科学—岩土工程]