构造节理偏压对隧道结构安全性影响研究

A Study of the Effects of the Bias of Tectonic Joints on the Safety of the Tunnel Structure

密集的构造节理,容易在施工中引起掉块、片帮、剥落、坍塌等工程灾害,且容易使隧道初期支护结构处于偏压状态,对支护结构安全性十分不利。从隧道力学的基本理论出发,依据实测围岩压力值,建立荷载—结构模型,对隧道初支内力进行分析,计算其安全系数,评价粉质黏土段施工采用的初支结构的安全性。计算结果表明:构造节理偏压对隧道支护结构受力较为不利,围岩压力呈不对称分布时,初期支护抗拉安全性较差,需根据实际偏压情况适当加强初期支护参数。

Concentrated tectonic joints often lead to engineering disasters such as dropping pieces, rib spalling,and spalling and sloughing,in which case the primary supporting structure of the tunnel is often put under bias, which often harms the safety of it. Upon the basis of the basic theory of the tunnel mechanics,and according to the practically-measured values of the pressure of the surrounding rock,a load-structure model is established in the paper,which is used for analyzing the internal forces of the primary support of the tunnel,calculating their safety coefficient,and evaluating the safety of the primary supporting structure adopted for the construction in the silty clay section. The calculated results show that the bias of tectonic joints has a compara- tively unfavorable effect on the supporting structure of the tunnel. When the pressure of the surrounding rock is unsymmetrical- ly distributed,the safety of the primary support is comparatively poor in tensile strength, in which case the primary support needs to be strengthened according to the practical situation of the bias.