北京光彩大厦深基坑开挖现场监测与理论分析

Field Measurements and Theoretical Analysis in Deep Excavation around Beijing Brilliance Edifice

由北京光彩大厦深基坑开挖过程中的监测结果及机理分析,得出以下结论:实施早期降水可在基坑整体刚度形成前有效利用基质吸力减小桩顶的侧移量;支护结构整体空间刚度的较早形成可以有效减小基坑的水平侧移;锚杆张拉锁定值小,在锚固体侧可引起负摩阻力;由实测值总结得出摩阻力值在锚固体侧的分布呈二次函数关系;桩身最大位移可能发生在桩身刚度较弱的截面;支护结构与土相互作用的结果,造成土压力实测值与经典理论计算值在分布规律上存在较大的差别。

The field measurements and theoretical analysis are insufficient in Beijing urban deep excavation. The conclusions were drawn based on the field measurements and the mechanism analyses of Brilliance edifice deep excavation in Beijing: Before the whole rigidity of the anchored pile support systems was formed, dewatering was carried out in the soil, the lateral displacement of the pile tip was minimized by using the matrix suction effectively; The earlier the anchored pile support systems were formed, the less lateral displacement was obtained ; The negative skin friction was induced at the external of the anchor when the stretch locking stress was small; The data show that the distribution function of skin friction along the anchor is quadratic; The maximal lateral displacement may occur at the weakest section of a pile; The result of soil-structure interaction causes difference between field and classical theory calculation at the lateral earth-pressure distribution.