基于统一强度理论的灰土桩复合地基挤密影响区半径计算  

Radius calculation of compacted zone in lime-soil composite foundation based on unified strength theory

作　　者：崔莹[1,2] 赵均海[1] 张常光[1] 孙珊珊[1] 

机构地区：[1]长安大学建筑工程学院,西安710061 [2]西安石油大学机械工程学院,西安710065

出　　处：《岩土力学》2013年第4期1116-1120,1139,共6页Rock and Soil Mechanics

基　　金：国家自然科学青年基金资助(No.41202191);陕西省自然科学基金资助(No.2011JM7002);教育部博士点基金资助(No.20110205130001)

摘　　要：灰土桩复合地基因桩体鼓胀变形使得桩间土体挤密,可以确定其挤密影响区范围,对评价地基加固效果有着十分重要的意义。采用统一强度理论,结合桩土变形协调条件,推导出复合地基沉降量与挤密影响区半径的关系式,并讨论不同b值、不同桩径d、不同深度条件下挤密影响区半径的变化趋势及影响特性。研究表明,挤密影响区半径随着地基深度的增加而减小,灰土桩最佳挤密深度范围为桩顶至1/3桩长深度之间;挤密影响区半径在1.51d～1.68d(d为桩径)之间,增大d可以有效扩大挤密影响区半径;应考虑中间主应力效应对岩土材料强度发挥的积极作用。When lime-soil composite foundation bearing load, the expansion deformation of lime-soil piles would compact soil around and exert pressure on soil and piles. To enhance the reinforcement effect of the lime-soil composite foundation, it is critical to identify the radius of compacted zone. Based on the unified strength theory and taking the conditions of compatible deformation of soil and piles into consideration, the formula describing the relationship between settlement of composite foundation and radius of compacted zone has been derived. Furthermore, the various elements influencing compacted zone radius and the trend of the zone radius changing under different values of b, different pile diameters, and different foundation depths are discussed as well. The research results indicate that the radius of compacted zone decreases with the increase of foundation depth when the b value and pile diameter are invariable. The results also show the optimal range of compacted zone along the composite foundation depth is from the pile top to the 1/3 length of pile. The radius of compacted zone varies from 1.51 d to 1.68d under different conditions of b value, where d is the diameter of pile. And radius of compacted zone expands along with increase of the pile diameter d, when the b value and foundation depth are invariable. To exert the strength of material such as soil, the solution considered the intermediate principal stress has positive effect on the ultimate strength of material.

关 键 词：统一强度理论 复合地基 灰土桩 挤密影响区 平面应变 

分 类 号：TU470[建筑科学—结构工程]