黄雪峰^1,2，  张建华¹，  马良荣³，  朱勃霖⁴，  邱  爽¹
    （1 兰州理工大学土木工程学院，兰州730050；2 解放军后勤工程学院军事建筑工程系，重庆400041；3 宁夏电力设计院，银川750000；4 兰州大学资源环境学院，兰州730000）

[摘要] 通过对湿陷性黄土大直径旋挖嵌岩灌注桩静载荷试验和桩身应力测试，对其桩身内力、荷载传递、侧阻力、端阻力及桩端阻力与桩侧阻力的相互关系等内容进行了试验研究。分析表明：1）良好的嵌岩桩桩岩胶结状况对嵌岩段和上覆土层桩侧阻力的发挥有较大影响；2）桩端承载性状对桩侧阻力强化效应发生的前提条件是桩端阻力承担一定的荷载，强化效应一般可使桩侧阻力提高20%~ 50%；3）桩端阻力对桩侧阻力的强化效应不仅表现在桩端附近，在桩身上部土层中也有强化效应现象。上述关系可以提高嵌岩桩桩侧阻力及单桩承载力，进一步进行桩基进行优化设计。
[关键词] 嵌岩桩；载荷试验；侧阻力；端阻力；强化效应
中图分类号：TU473.1    文献标识码：A  文章编号：1002-848X( 2011) S2-0351-05

Research on strengthening effect of rock-socketed characters of cast in place pile on shaft resistance for collapsible loess
Huang Xuefeng^1,2,  Zhang Jianhua¹,  Ma Liangrong³,  Zliu Bolin⁴,  Qiu Shuang¹
(1 School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China; 2 Department of Architectural Engineering, Logistical Engineering University of PLA, Chongqing 400041, China; 3 Ningxia Electric Power Design Institute, Yinchuan 750000, China; 4 College of Earth and Environment Science, Lanzhou University, Lanzhou 730000, China)

Abstract: This paper presents the test research on characteristic of intemal force of pile, the load transfer behaviors, tip resistance, shaft resistance, and the relationship between the shaft resistance and the tip resistance, by the pile load test and axial stress tests oflarge diameter bored cast-in-place rock-socket pile in collapsible loess. Analysis suggests: 1) good pile-rock cementation status greatly influences the upper pile side and rock-socket section shaft resistance; 2) the shaft resistance strengthening effect of pile bearing performance( bearing behavior of pile)  is based on the function of tip resistance, and strengthening effect will generally play shaft resistance increased by 20%~50%;3)the shaft resistance strengthening effect of tip resistance is shown not only nearby the pile tip, but also in the soil about the upside of pile. The relationship above can improve the side resistance of rock-socketed pile and load-bearing capability of each pile, and it is helpful to optimize the design of pile.
Keywords: rock-socket pile; pile load test; shaft resistance; tip resistance; strengthening effect