摘要
根据岩溶区嵌岩桩的工程特点,对现有的梁板结构进行优化,将岩溶区嵌岩桩溶洞顶板简化为边界是弹性支承的三铰拱模型;基于尖点突变理论导出了能量势函数和分叉集方程,建立岩溶区嵌岩桩尖点突变模型平衡曲面;根据岩溶区嵌岩桩溶洞顶板突变失稳的条件,提出岩溶区嵌岩桩极限承载力及溶洞顶板安全厚度的确定方法;从拱杆的线刚度与支承弹簧刚度比、溶洞顶板跨径及顶板厚度三个方面对溶洞顶板的稳定性进行参数分析,结果表明:溶洞顶板稳定性随拱杆的线刚度与支承弹簧刚度比的增加而降低;当溶洞顶板跨径小于4倍桩径时,溶洞顶板处于稳定状态;当顶板厚度大于2倍桩径时,溶洞顶板不易发生突变失稳。最后结合工程算例验证本文方法的可行性和合理性。
According to the engineering characteristics of rock-socketed pile in karst areas,the existing beam-slab structure is optimized,and the cave roof of the rock-socketed pile is simplified as a threehinged arch model with elastic supports. The energy potential function and bifurcation set equation are derived based on the cusp catastrophe theory,and the equilibrium surface of the cusp catastrophe model under the rock-socketed pile in karst region is also established. According to catastrophic instability condition of rock-socketed pile embedded on cave roof,the method for determining the ultimate bearing capacity of rock-socketed pile and the safe thickness of cave roof are put forward;The stability of cave roof is analyzed from three aspects:the ratio of the linear stiffness of the arch to the supporting spring stiffness,the span of cave roof and the thickness of cave roof. Results reveal that:the stability of cave roof decreases with the increase of the ratio of the linear stiffness of the arch to the supporting spring stiffness;When the span of the roof is less than 4 times the diameter of the pile,the roof of the cave is in a stable state;When the thickness of the roof is more than 2 times the diameter of the pile,the roof of the cave is not susceptible to mutation instability;The feasibility and rationality of the method in this paper are verified by the engineering example.
作者
赵明华
陈言章
肖尧
杨超炜
ZHAO Minghua;CHEN Y anzhang;XIAO Yao;YANG Chaowei(Institute of Geotechnical Engineering,Hunan University,Changsha 410082,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2020年第2期167-173,278,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金项目(51478178)资助。
关键词
岩溶
嵌岩桩
弹性三铰拱
突变理论
稳定性
karst
rock-socketed pile
elastic three-hinged arch
catastrophe theory
stability
