广州某花岗岩地块单桩承载力特征值综合确定

Comprehensive Determination of Characteristic Value of Bearing Capacity of Single Pile in a Granite Block in Guangzhou

全风化及强风化花岗岩极限侧阻由于其矿物组成及含量不同而差别大,且受地下水及施工工艺的影响较大,难以取值。工程根据静载试验成果,确定其单桩竖向抗压极限承载力,采用规范经验公式,返求全、强风化花岗岩极限侧阻,再与规范经验值对比,综合确定其推荐值,最后根据设计荷载要求,确定单桩竖向抗压承载力特征值。综合确定的全、强风化花岗岩极限侧阻力标准值已经考虑了矿物组成及含量、风化环境、地下水、成桩工艺、泥浆比重等多因素的影响,对特定场地及特定施工工艺下的单桩竖向抗压承载力特征值确定具有直接的指导意义。

The ultimate shaft resistance of completely weathered and strongly weathered granite varies greatly dued to its different mineral composition and content,and groundwater and construction technology,so it is difficult to take a value.According to the results of static loading test,the ultimate vertical bearing capacity of a single pile is determined in this project.The empirical formula of standard is used to find the ultimate shaft resistance of completely and intensively weathered granite.Then compared with the standard empirical value,the recommended value is determined comprehensively.Finally,characteristic value of vertical bearing capacity of single pile is determined according to the design load requirements.The ultimate shaft resistance of completely and strongly weathered granite has taken into account the influence of mineral composition and content,weathering environment,groundwater,pile forming process,mud proportion and other factors.It has direct guiding significance for the determination of the characteristic value of the vertical compressive bearing capacity of single pile at a specific site and under a specific construction process.