摘要
在新型板桩码头结构中,带卸荷承台板的直立灌注桩群桩基础被用来与前墙一起共同承担土体侧向位移所产生的侧向荷载,这些直立桩的工作机制类似抗滑被动桩,但其桩土相互作用程度远没有达到极限状态。结合20万吨级卸荷式板桩码头结构设计方案的验证,开展了多组土工离心模型试验,测量了各排灌注桩两侧土压力,得到了均质细砂地基中两种承台群桩基础中桩身侧压力分布,其特征是桩身上部侧压力为正,作用方向与土体位移一致,而桩身下部侧压力为负。各排桩的侧压力零值点约位于港池泥面线下4倍桩径位置处,可根据侧压力零值点分界线将桩身划分为上部被动段和下部主动段进行设计处理。为了确定被动段侧压力大小,引入被动段桩宽比,将桩侧压力与朗肯主动土压力相关联,结果发现,海侧桩被动段桩宽比接近3.0,明显大于中间桩和陆侧桩,因此,承台群桩基础设计中,被动段可以近似按3倍朗肯主动土压力作为设计值考虑。
The pile group of vertical cast-in-place piles with relief platform has been successfully introduced into innovative sheet-pile wharfs to withhold lateral load due to horizontal soil movement along with its front wall. The work mechanism of the piles is similar to that of stabilizing piles, but their pile-soil interaction degree is far below the limit state. In order to study the distribution of the lateral pile-soil pressure along pile for the formation of its design method, geotechnical centrifuge model tests of two schemes are conducted to simulate 200,000-tonnage sheet-pile wharfs with relief platform in fine sand. The pile-soil pressure distribution is obtained by measuring the earth pressures at its two sides. The characteristic is that the lateral pile-soil pressure is positive for the upper part, meaning the same direction to soil movement, and negative for the lower part. And the position of zero value of pile-soil pressure is below the mud line of harbor basin by about four times the pile diameter. By using the position of zero pile-soil pressure as the demarcation line, each pile can thus be divided into the upper passive part and the lower active part, as is done in stabilizing piles. In order to estimate the pile-soil pressure of pile＇s passive part, it is correlated with the Rankine active pressure by introducing an average breadth ratio on the passive part of pile. It is found that the breadth ratio of pile＇s passive part is about 3.0 for seaside piles, much bigger than that for the middle and landside piles. Therefore, the pile-soil pressure of pile＇s passive part can be taken to be 3 times the Rankine active pressure in the design of pile groups with relief platform.
作者
徐光明
任国峰
顾行文
陈爱忠
李乐晨
XU Guang-mlng1,2, REN Guo-feng1, 2, GU Xing-wen1 ,2, CHEN Ai-zhong3, LI Le-che4(1. Nanjing Hydraulic Research Institute, Nanjing 210029, China; 2. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing 210029, China; 3. Licheng Electronic Device Producer, Liyang 213300, China; 4. School of Architecture and Environment, Sichuan University, Chengdu 610000, Chin)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2018年第3期502-511,共10页
Chinese Journal of Geotechnical Engineering
基金
中国交通建设股份有限公司科技研发项目经费的大力支持
关键词
承台群桩基础
灌注桩
桩侧压力
桩宽比
被动段
pile group with relief platform
cast-in-place pile
lateral pile-soil pressure
breadth ratio of pile
passive part
作者简介
徐光明（1963-），男，教授级高级工程师，主要从事土工离心模型试验研究。E-mail：gmxu@nhri．cn。;通讯作者（E-mail：xwgu@nhri．cn）
