竖向激励场下考虑桩土滑移的单桩动力性态  

Response of single piles to vertical excitation with pile-soil slip

作　　者：吴鹏[1] 任伟新[1] 

机构地区：[1]中南大学,湖南长沙410075

出　　处：《土木工程学报》2009年第6期92-96,共5页China Civil Engineering Journal

基　　金：国家自然科学基金(50708115);中国博士后科学基金(20070410308);中国博士后科学基金(20081347)

摘　　要：较大竖向地震激励下,桩土间有可能发生桩土相对滑移。为了考虑这种强震条件下桩土动力响应性态,提出了考虑该桩土滑移的桩土界面力的传递模型,并建立动力微分方程进行求解,得到桩基动力响应的位移显式表达式。定义了桩基动力响应系数,得到无限桩长、纯摩擦桩和端承桩等几种情况下的桩基动力响应系数的表达式。数值计算结果表明:考虑桩土滑移的桩基动力响应与不考虑桩土滑移的计算结果差距较大,尤其是在桩土模量比较大的情况下,差距更大;考虑桩土滑移的计算结果在低频段就不接近1,且出现振荡的临界频率点较低。因此,更为精细的桩土动力接触机理的研究尤其是试验研究十分必要。There would be relative slip between pile and soil under strong vertical earthquake excitation. A force transfer model considering the slip between pile and soil was presented. A dynamic differential equation was established and solved to obtain the explicit displacement response of the pile. A kinematic response coefficient of the pile was defined, and formulations of the kinematic response coefficient for infinitely-long piles, completely free-toe piles and end-bearing piles were obtained. Numerical results showed great difference if slip between pile and soil is considered, especially when ratio of pile modulus to soil modulus is large. The kinematic response coefficient of the pile is not close to one even if the frequency is low and the critical frequency of beginning oscillation is less if slip between pile and soil is considered. So more careful study especially experiment study on the contact mechanism between pile and soil is necessary.

关 键 词：桩土滑移 竖向地震 桩土动力相互作用 桩基动力响应系数 WINKLER模型 

分 类 号：TU473.1[建筑科学—结构工程]