冻融条件下的寒区隧道围岩压力计算方法

Calculation Method of Surrounding Rock Pressure for Tunnel in Cold Region under Freezing-thawing Conditions

为了明确寒区隧道承受的围岩荷载,给其支护结构设计提供科学依据,节约隧道建设成本,文章针对围岩压力的计算方法进行了研究。分析并给出了不同冻土段考虑冻融作用的围岩压力计算方法:工程冻土段的围岩压力不考虑冻、融条件的影响,可直接用《公路隧道设计规范》的方法进行计算;多年冻土段浅埋隧道围岩压力,在融化条件下采用文章推导提出的公式计算;其余情况下围岩压力采用《公路隧道设计规范》中的方法进行计算,并根据冻融条件,分别采用冻、融条件下的围岩力学指标标准值,其中多年冻土深埋段围岩压力不考虑冻、融条件的影响,均取融化条件下的围岩力学参数进行计算。最后将该方法应用于姜路岭隧道设计荷载计算分析中加以阐释。

In order to determine the surrounding rock loads borne by the tunnel in cold region and to provide a scientific basis for the design of its supporting structures and to save the tunnel construction cost,this article studied the calculation method of surrounding rock pressure.The calculation method of surrounding rock pressure considering the freezing and thawing role in different permafrost zones was analyzed and given;the effect of freezing and thawing conditions is not considered for the sur-rounding rock pressure in engineering permafrost section, it can be directly calculated by the method of ＂Design Code for Highway Tunnels＂; the surrounding rock pressure of shallow-buried tunnel in multi-year permafrost section is calculated by the formulas derived and proposed in this article under the freezing-thawing condition; the surrounding rock pressure in other cases is calculated by the method of＂Design Code for Highway Tunnels＂, and according to the freezing-thawing condition, the mechanical parameters of surrounding rock under freezing and thawing conditions are adopted re-spectively,and for the surrounding rock pressure of deep-buried multi-year permafrost section, the mechanics parameters of surrounding rock under the thawing conditions are used for calculation with- out considering the impact of freezing and thawing conditions.Finally,this method was applied to and further described in the design load calculation and analysis of Jiangluling Tunnel.