滇中红层软弱围岩隧道变形开裂原因分析及处治措施研究

老东山隧道在施工过程中多次出现初期支护变形开裂的情况，为保证施工安全和进度，通过对现场围岩变形实测数据进行深入分析，确定了隧道初期支护的变形开裂特征。从围岩的岩性条件、地下水条件、地质构造条件以及施工管理等方面，探讨滇中红层隧道产生大变形的原因和机制，认为它是围岩膨胀变形与其他因素综合作用的结果。进一步确定了强化超前地质预报、增加径向注浆加固、加强初期支护、控制各工序的施工时间和间距等变形控制措施，隧道变形开裂得到有效控制。

Causes and Countermeasures for Deformation and Cracking of Tunnel in Weak “Dianzhong Red Strata”

Laodongshan tunnel is located in typical ＂Dianzhong red strata＂. During the construction of the tunnel, de- formation and crack occur to the primary support. The deformation characteristics of the primary support are obtained by means of analysis on the monitoring data. The causes for the serious deformation of the tunnel in ＂Dianzhong red strata＂ are discussed in terms of rock mass lithology, groundwater, tectonic structures and construction management. Counter- measures, including strengthening the advance geology prediction, performing radial grouting, strengthening the primary supporting and controlling the duration and spacing of the construction process, are proposed. In the end, the deforma- tion and cracking of the tunnel are brought under effective control.