运营隧道裂损衬砌置换后新结构受力特性测试

为了分析衬砌置换的适用性,依托某二级公路隧道治理工程,对裂损二次衬砌置换后的结构受力特性进行了现场测试.测试结果表明:原初期支护与新施作的衬砌间接触压力较小,其值低于围岩松动压力计算值,且其分布呈现较为明显的非对称性;二次衬砌内力分布规律与接触压力分布规律类似,其轴力及弯矩值整体较小,表明衬砌置换后并未发挥明显承载作用,反映出依托工程采用衬砌置换手段并不合理.结合现场测试结果及衬砌置换施工实际情况,对衬砌置换的适用性进行了讨论,并给出了衬砌置换的适用条件及施工时的注意事项.

Mechanical characteristics test on the new structures after cracked lining replacement in an operating tunnel

In order to analyze the applicability of lining replacement method,the mechanical characteristics of the new structures were tested in-situ after the replacement of cracked linings based on the reinforcement engineering of a second class highway tunnel.The test results are as follow.The contact pressures between original initial supports and the newly constructed secondary linings are smaller,whose values are lower than the calculated values of surrounding rock relaxed pressure,and the contact pressures are not equally distributed.The internal force distribution law of the secondary linings is similar with that of the contact pressures,and the axial forces and moments of the secondary linings are overall smaller,which shows that the new secondary linings have not worked evidently after lining replacement,and the lining replacement method used in the supported engineering are not necessary.According to the test results and the actual conditions of lining replacement construction,the necessities of lining replacement method are discussed,and the appropriate conditions and construction notifications of this method are also given in this paper.