基于Hoek-Brown强度准则的嵌岩桩极限承载力确定  

Detemination of ultimate bearing capacity of rock-socketed pile based on H-B strength criterion

作　　者：赵明华[1] 雷勇[1] 马缤辉[1] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082

出　　处：《水利学报》2011年第9期1058-1064,1074,共8页Journal of Hydraulic Engineering

基　　金：国家自然科学基金资助项目(50578060)

摘　　要：考虑岩体结构的完整性、岩块单轴抗压强度及三向应力等因素的影响,引入Hoek-Brown岩石强度准则,采用Lambe变换,建立了较为实用的嵌岩桩桩侧摩阻力模型。然后基于简化的桩端岩体破坏模式,利用极限平衡原理,推导了三向压力下嵌岩桩桩端阻力的计算公式,进而获得嵌岩桩极限承载力计算公式。对公式参数分析表明:岩体质量对摩阻力影响较大,岩体质量越好,摩阻力τr越大,反之越小;岩体质量评价指标RMR值为100时,摩阻力τr可达到0.4σc;岩体质量评价指标RMR值为10时,摩阻力τr接近0.01σc。最后以2个工程实例对本文计算方法进行了验证。Considering the impacts of integrity of rock structures,rock uniaxial compressive strength and three-dimensional pressure,the Hock-Brown strength criterion for rock mass was introduced to obtain a new practical model of skin friction for rock-socketed piles with Lambe Transformation.Then,based on the failure mode of rock mass at the pile tip,a formula of rock-socketed pile tip resistance under three-dimensional pressure was derived by means of the ultimate equilibrium principle.Thus the ultimate bearing capacity formula of rock-socketed pile was obtained.Parametric analysis shows that rock mass quality influences intensively on friction resistance,the better the rock mass quality is,the higher the friction resistance τ it would be.When the rock mass quality evaluation RMR value is 100,the friction resistance τ can mostly reach 0.4 times σc;while the RMR value is 10,the friction resistance τ can approach 0.01 times σc.Finally,two examples of projects are given to verify the calculation method.

关 键 词：桥梁工程 嵌岩桩 岩体力学 HOEK-BROWN强度准则 极限承载力 

分 类 号：TU473.1[建筑科学—结构工程]