铁路运营隧道衬砌背后接触状态及其分析

STUDY OF CONTACT STATE BEHIND TUNNEL LINING IN PROCESS OF RAILWAY OPERATION AND ITS ANALYSIS

铁路隧道衬砌背后接触状态可分为衬砌背后接触密实、衬砌背后接触松散和衬砌背后空洞3种情况,其中,衬砌背后接触松散和衬砌背后空洞统称为衬砌背后接触不良,是常见的隧道质量缺陷。研究表明:衬砌背后接触不良是诱发隧道病害的重要原因,直接影响到隧道结构的安全性。通过对100余座铁路运营隧道衬砌无损检测及统计分析,取得以下结论:(1)同等条件下,单层衬砌比复合式衬砌更易出现衬砌背后接触不良状况,且单层衬砌背后接触不良程度高于复合式衬砌;(2)衬砌背后接触不良段所占比例及严重程度与围岩级别有密切关系,在隧道围岩稳定性较差的区段更为严重;(3)衬砌背后接触不良状况随断面位置而变化,以拱顶处最大,拱脚减小;(4)衬砌背后空洞的存在受到隧道设计理念、工程质量控制和运营养护水平等因素的影响,而衬砌背后及时的回填注浆则是控制的关键。取得的隧道衬砌背后接触状态及其分布规律可为结构缺陷的病害演化及致灾机制的研究提供参考与借鉴。

There are three types of contact states between the primary linings and the secondary linings for the railway tunnels. Those are tight contact state, loose contact state and voids. Both the loose contact state and the voids behind the linings can be regarded as poor contact, which are deemed as typical tunnel quality defects. The research results show that the poor contact states have great influence on tunnel structure safety. General law of contact states behind railway tunnel linings in China is obtained according to the lining nondestructive test data of more than 100 railway tunnels. The research results show that： （1） Poor contact states behind linings are more incidental and serious in single shell lining than in the composite lining under the same conditions. （2） The occurrence proportion and severity of poor contact conditions behind linings have a close relationship with the surrounding rock classification; and they are more disadvantageous in the poorer surrounding rock. （3） The occurrence proportion and severity of poor contact states behind linings are affected by the positions of the poor contact states around the tunnel cross-section. The negative effects of the contact states decrease from the tunnel crowns to tunnel feet. （4） The appearance of the voids is affected by tunnel design principle, construction quality control, operational maintenance efficiency, etc. The prompt contact grouting between the primary lining and surrounding ground is the key to control this undesired phenomenon. The results obtained in this study can provide useful reference for studying the contact states between the primary linings and the secondary linings. It will also be helpful to study the development of the defects in the tunnel structure system.