论文部分内容阅读
某既有线桥梁在上部荷载长期作用下,桥墩产生沉降和倾斜,危及行车安全。勘察表明,该桥墩基础下分布有溶洞。基于突变理论,根据岩溶区桩下卧溶洞顶板失稳破坏条件,确定了位于溶洞顶部原桩的承载力;在此基础上,针对岩溶分布特征和地基承载特性,采用增补桩基-扩大承台主动加固法对其进行加固,通过理论计算确定合理桩长;同时,采用数值模拟软件,分析了桥墩基础加固前后的稳定性,以及增补桩基桩长与桥墩基础沉降和倾斜的关系。结果表明:数值计算结果与理论计算结果吻合,原桥墩基础承载力不满足设计要求,增补桩的合理长度为14.5 m,已穿透溶洞,此时承台中心沉降为6.9 mm,纵桥向承台最大沉降差为0.89 mm。
Under the long-term action of the upper part of a existing bridge, the settlement and inclination of the bridge pier will endanger the traffic safety. Investigation shows that there are karst caves distributed under the piers. Based on the catastrophe theory, the bearing capacity of the original pile located at the top of the cave is determined according to the failure conditions of the roof of the cave in the karst area. Based on the distribution characteristics of the karst and the bearing capacity of the foundation, And the reasonable reinforcement length was calculated by theoretical calculation. At the same time, using the numerical simulation software, the stability of the pier foundation before and after consolidation was analyzed, and the relationship between the pile length of the added pile and the settlement and inclination of the pier foundation was analyzed. The results show that the numerical results agree well with the theoretical results. The bearing capacity of the foundation of the original piers does not meet the design requirements. The reasonable length of the supplementary pile is 14.5 m and has penetrated the cave. The settlement of the center of the bearing platform is 6.9 mm. The maximum settlement difference is 0.89 mm.