炸山嘴隧道围岩大变形特征及其控制措施

强风化砂岩围岩自身承载能力弱,遇水后其强度迅速降低,发生围岩大变形的概率极大。该文以固西公路炸山嘴隧道工程为依托,通过现场监测,分析了强风化砂岩段围岩大变形的特点及其变形机理,并结合实际施工情况,提出了强风化砂岩围岩大变形的控制措施。得出在强风化砂岩段发生大变形的条件下,可通过施做临时刚护拱、临时仰拱以及临时支撑等加固补强措施,以稳住围岩变形;在强风化砂岩地区开挖隧道,应提高其支护体系的整体刚度,并在换拱时采用微型爆破、逐榀换拱等方法以减少对围岩的扰动,同时应及时施做仰拱和二次衬砌。所得结果为相似地质条件下隧道的施工提供借鉴。

Characteristic of Large Deformation and Its Control Measures of Surrounding Rock in Zhashanzui Tunnel

The bearing capacity of strong weathered sandstone surrounding rock is weak,its strength decreases rapidly after encountering water,and the probability of large deformation of surrounding rock is extremely. The article relies on the Zhashanzui Tunnel of Guxi Road,through site monitor measurement,the characteristics and deformation mechanism of the large deformation of strong weathered sandstone surrounding rock are analyzed. Combined with the actual construction conditions,the control measures for large deformation of strongly weathered sandstone surrounding rock are put forward. It concludes that under large deformation conditions of strong weathered sandstone,the deformation of surrounding rock can be stabilized by reinforcement measures such as temporary rigid arch,temporary inverted arch and temporary support. The global stiffness of its supporting system should be improved when the tunnel is excavatied in strongly weathered sandstone area,the method of micro blasting and replacing the trusses to archstep one by one should be used to reduce the disturbance to surrounding rock,and the invert arch and secondary lining should be done in time. The results provide reference for tunnel construction under similar geological conditions.