基于H-B强度理论的桩端岩层安全厚度确定  

Study on the Safe Thickness of the Rock Mass at the End of the Pile Based on Hoek-Brown Strength Criterion

作　　者：赵明华[1] 周磊[1] 雷勇[1] 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2010年第6期1-5,共5页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(50378036)

摘　　要：针对岩溶区桩端岩层安全厚度确定中存在的问题,引入能综合考虑岩体质量及三向应力的影响的Hoek-Brown岩体经验强度准则,确定了岩体抗拉强度计算公式,并采用Lambe变换,建立了较为实用的岩体剪切破坏强度公式.基于桩端岩体破坏模式,确定了桩端岩层安全厚度的计算方法.参数分析表明:RMR值对桩端岩层安全厚度有强烈影响,RMR值越高,安全厚度越小,反之越大.对于一般天然下自稳状态的溶洞顶板,安全厚度取3倍桩径较为合理.最后结合工程实例对本文计算方法进行了验证.To deal with the problems of safe thickness at the end of the pile in Karst areas,the Hoek-Brown rock mass strength criterion was introduced,which considered the influence of rock mass quality and triaxial stress.The formula of rock mass tensile strength was confirmed,and a practical formula of rock mass shear strength was established by the use of Lambe transformation.Then,the computational method of the safe thickness of the rock mass at the end of the pile was determined on the basis of the failure mode of the rock mass at the end of the pile.Parametric analysis has shown that the Rock Mass Raling（RMR） value has a strong effect on safe thickness.The higher the RMR value,the smaller the safe thickness and the greater the contrast.For the general state of the natural homeostasis of the Karst cave roof,a safe thickness value 3 times the pile diameter is reasonable.Finally,a sample project was carried out to verify this calculation method.

关 键 词：桩基础 安全厚度 冲切破坏 HOEK-BROWN强度准则 

分 类 号：TU473.1[建筑科学—结构工程]