杭州深厚软土层钻孔灌注桩单桩承载特性研究  

Research on Vertical Bearing Capacity of Single Bored Pile in Deep Soft Stratum of Hangzhou

作　　者：梁师俊[1] 诸葛政桦 朱海东[1] 

机构地区：[1]浙江建设职业技术学院城市建设工程系,杭州311231 [2]浙江江南建设工程监理公司,杭州310007

出　　处：《建筑科学》2013年第5期44-48,共5页Building Science

基　　金：浙江省教育厅科研项目(Y201225912)

摘　　要：杭州市某高架桥选用后压浆钻孔灌注桩,为了掌握钻孔灌注桩在该软土层的承载特性,共设计了一组三根试桩进行单桩竖向抗压试验和桩身高应变试验,试桩中安装了振弦式钢筋应力计、滑动测微仪和土压力盒以反映桩侧摩阻力、桩端阻力及竖向承载力。通过对试验数据进行计算及对比分析,结果表明:杭州软土层钻孔灌注桩表现为典型摩擦桩受力性状;单桩摩阻力由上部土层到下部土层依次发挥,浅部土层在达到极限摩阻力后,随着加载的增大,由于桩周土体发生了滑移破坏,桩侧摩阻力会有所降低;桩身高应变动测试验结果与静载试验结果接近,但桩侧、桩端分担比例与静载试验结果稍有差别。The layers of a viaduct bridge construction site in Hangzhou are mainly clay, silt and silt sand. One group of the bored test piles with post pressure-grouting（a total of three piles） are designed to undertake the bearing behavior test by using single pile vertical static load test and high strain test to master the engineering properties in the viaduct bridge construction site. ln-situ monitoring aiming at observing the pile shaft friction and pile tip resistance was conducted, in which vibrating wire reinforcement meter and sliding micrometer and earth pressure cells were adopted. After the test, the results of the data analysis show that the bored pile in Hangzhou soft soil works as the typical friction pile on force character. The measured data also indicate that the side friction resistance of the bored pile shaft gradually occurs from the top down to the lower part of soil layer, and the shaft resistance softening is observed when the load of the superficial part of soil layers reaches the ultimate shaft resistance. Furthermore, the results of the pile body high strain test are close to the results of the static load test, but the load proportion of pile shaft and pile tip has a little difference from the static load test.

关 键 词：单桩承载特性 静载试验 高应变试验 桩身轴力 桩侧摩阻力 桩端阻力 

分 类 号：TU473.14[建筑科学—结构工程] TU471.8[建筑科学—土工工程]