冻、融土中桩的水平受力特性模型对比试验研究  

EXPERIMENTAL STUDY OF CONTRAST MODEL FOR CHARACTERISTICS OF PILE UNDER LATERAL LOAD ACTION IN FROZEN AND THAWED SOILS

作　　者：张嘉文[1] 张鸿儒[1] 宋佳鹏 刘亚伟[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《工业建筑》2013年第10期66-70,共5页Industrial Construction

基　　金：国家自然科学基金项目(90715013);国家级大学生创新训练项目(123003)

摘　　要：通过模型试验,对不同温度条件(室温条件(20℃)、冻结条件(-10℃)、融土条件)下的饱和砂土分别进行桩头位移-水平荷载关系、桩身弯矩和挠度分布规律以及土体的刚度变化等桩-土相互作用等的研究。此外引入工程中常用的m法进行对比验证,探讨m法的适用条件。研究发现:室温土中桩在小荷载作用下产生明显的桩头侧移和挠曲变形,桩身弯矩呈现自上而下先大后小的分布规律;冻土中形成的大量冰胶结物使土体刚度得到极大提高,大荷载难以使桩基发生大的变形和侧移,桩身最大弯矩埋深显著减小;上层融土降低了桩头位置土的刚度,使得桩显示出室温土与冻土的双重性质,桩身弯矩最大值较室温土、冻土条件下更大,其埋深较冻土中大;在多年冻土区进行桩基施工应当重视冻土层的保护;m法在常温土中具备很好的安全性和适用性,但在冻、融环境下应用时差异较大。Through model test, pile-soil interaction problems in saturated sandy soil under the different temperature conditions： room temperature （20 ℃ ） , freezing conditions （ - 10 ℃ ） , and thawed soil conditions, were studied separately. The relationship between lateral load vs displacement of pile head, the deflection and bending moment distribution of pile and the stiffness change of soil were mainly investigated. In addition, the m-method was used for comparison, and the suitable conditions for m-method were discussed. The results showed that obvious flexure deformation and lateral movement oecured at pile head of the pile under small load in room temperature soil, and the bending moment of the pile shaft was that it increased first and then decreased from top to bottom; large amounts of ice cements made soil stiffness greatly improve, it was difficult for a large load to make pile foundation produce big deformation and lateral movement. The maximum bending moment of pile depth decreased significantly; upper thawed soil decreased the stiffness of the soil at pile head position, which made the pile showed the dual property of room temperature and frozen soil. The maximum bending moment value was higher than that in room temperature soil and frozen soil. When doing a construction of pile foundation in permafrost areas, much attention should be paid to the protection of frozen soil. The m-method had good safety and applicability in room temperature soil, but there was a big gap when applying it in frozen and thawed soils.

关 键 词：室温土 冻土 融土 水平荷载 M法 桩-土作用 

分 类 号：TU473.1[建筑科学—结构工程]