摘要
结合申嘉湖杭高速公路练杭段加固软土地基工程开展了塑料套管混凝土桩挤土效应的现场试验研究。设地表观测点观测桩打设过程中桩周土体隆起情况;采用绑定仪器的方形木桩等效模拟塑料套管混凝土桩研究不同时刻桩侧挤土压力和孔隙水压力的变化。结果表明打桩过程中在距桩中心约2.2倍沉管外径处地面隆起量最大,约为沉管外径的17.2%;打设完成第一根相邻桩(距离1.6 m)桩侧土压力及孔隙水压力增大10%～20%,其后随着打设桩距木桩距离的渐远,两次打桩后的土压曲线和孔压曲线变化不大,仅在下部桩端处变化较大;场地内桩打设完毕后,沉桩引起的超孔隙水压力逐步消散。根据实测数据建议塑料套管环刚度控制在8～16级。
Based on the practical strengthening soft soil foundation engineering in the Shanghai-Jiaxin-Huzhou-Hangzhou expressway of Lian-Hang section,the field test on compaction effect caused by piling plastic tube cast-in-place concrete pile was carried out.Some observation points were set on the surface to study the uplift of soil around the pile when driving pile. In order to facilitate the arrangement of instruments,the timber pile was used to simulate the plastic tube cast-in-place concrete pile equivalently,using it the change rules of lateral earth pressure and pore water pressure were studied.The test results show that the largest uplift value,approximately 17.2%of external diameter of immersed tube occurs at the 2.2 times distance of the external diameter of immersed tube away from the pile center.Both of lateral earth pressure and pore water pressure are increased by 10%to 20%respectively after the first adjacent pile（1.6 m away from the timber pile）driven.With the piles driving farther away,the adjacent changes of the pressure curves little,but is larger at the pile toe.The excess pore water pressure caused by piling dissipates gradually after the completion of pile construction.It is suggested that the ring stiffness of the plastic tube should be 8~16 grade according to the measured data.
出处
《西北地震学报》
CSCD
北大核心
2011年第B08期190-194,213,共6页
Northwestern Seismological Journal
关键词
塑料套管混凝土桩
挤土效应
现场试验
桩侧土压力
孔隙水压力
Plastic tube cast-in-place pile
Compaction effect
Field test
Lateral earth pressure
Pore water pressure
