软岩大变形偏压公路隧道变形与荷载作用特征  

Analysis on deformation and load action features of large-deformation bias highway tunnel in soft rock

作　　者：来弘鹏[1] 杨万精 谢永利[1] 

机构地区：[1]长安大学桥梁与隧道陕西省重点实验室,陕西西安710064 [2]西安市城乡建设委员会,陕西西安710003

出　　处：《中南大学学报（自然科学版）》2014年第6期1924-1931,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51008029;51378071);陕西省自然科学基金资助项目(2013JQ7030;2014KJXX-53);中央高校基本科研业务费专项资金项目(CHD2012ZD 019);国家留学基金资助项目(201206565026)

摘　　要：为解软岩大变形偏压公路隧道变形与荷载作用特征,以宜巴高速公路卧佛山隧道实体工程为依托,选取2个典型断面开展现场测试工作,对初期支护变形与受荷特征进行研究。研究结果表明:围岩非对称大变形隧道围岩前期变形速度快,稳定持续时间长,水平收敛值大;围岩压力前期增加速率快,变化持续时间长,水平围岩压力大、最大值出现在围岩较差一侧拱肩处;钢拱架在围岩较好一侧拱肩处出现压应力集中,在围岩较差一侧拱肩处出现拉应力集中,钢拱架扭曲变形严重;喷射混凝土在围岩较差一侧承受较大的拉应力,且超过混凝土的抗拉强度,大面积开裂剥落,围岩较好一侧压应力较大,但其值未超过C20喷射混凝土抗压强度;围岩非对称大变形隧道设计时应加大围岩较差一侧超前支护强度,加大预留变形量,加强初期支护,施工时宜采用预留核心土的三台阶开挖方法。In order to find out the distortion and load features of bias highway bedded with soft-rock and severe distortion, citing the project of Yi-Ba Highway Lying Buddha Tunnel in the study, field tests on two typical cross sections were carried out and the features of load and of supports distortion at early phase were analyzed. The results show that the surrounding rock of bias highway tunnel is at high speed of deformation during prior-period, which has stability of long duration and large value of horizontal convergence. The stress of surrounding rock at early stage adds at high speed, and also with changes of long duration. Heavy pressure lies in horizontal surrounding rock and the maximum value lies in the spandrel of comparative bad-condition side of surrounding rock. The concentrated comparative stress lies in the steel arch of good-condition side and concentrated compressive and tensile stress in the other side. The steel arch is severely distorted. Comparatively heavier tensile stress of shotcrete lies in the bad-condition side with serious cracks and large areas of spalling occurred, while the other side carries comparatively heavier compressive stress without meeting the compressive strength of C20 shotcrete. Ahead-of-supporting strength in bad-condition side should be increased, deformation allowances should be increased , primary supports should be increased, and three step excavation method and reserving core soil should be adopted.

关 键 词：隧道工程 软岩 大变形 偏压 

分 类 号：TU453[建筑科学—岩土工程] TU94[建筑科学—土工工程]