土拱效应、应力扩散效应、应力集中效应和桩承式路堤  

Soil Arch Effect, Stress Spreading Effect, Stress Concentrating Effect and Pile-supported Embankment

作　　者：华国强 

机构地区：[1]上海市建设工程管理有限公司,上海市200031

出　　处：《城市道桥与防洪》2017年第5期263-268,共6页Urban Roads Bridges & Flood Control

摘　　要：质疑土拱效应中存在土拱,因"无法探测土拱",使得土拱的形态、形成和应力转移的各种推测均无法验证,土拱效应的计算方法繁多而不能统一,"土拱"的假设制约了土拱效应理论的发展。分析了颗粒结构应力传递的特点,提出应力扩散效应是土体中应力分布基本特性的全新观点。根据应力在扩散范围内具有向强支承面自动集中获得平衡的规律,提出土体中还存在应力集中效应。当土体中应力集中现象发生重迭时,就会产生土拱效应。桩承式路堤中填土超过等沉面高度h0后,桩顶的应力集中效应覆盖整个路堤面,路堤即出现土拱效应典型的应力分布现象。土拱效应是土体抗剪强度通过应力扩散实现的应力转移现象,土拱效应中不存在土拱,土的应力集中效应和土拱效应都是土的应力扩散效应的衍生效应。提出计算桩承式路堤中等沉面高度h0的通用公式。等沉面高度h0不仅与桩净距有关,更与填土的性质有关。The article queries the soil arch existing in the soil arch effect. Owing to hard detecting the soil arch,the type and formation of soil arch, and various speculations of stress transfer are hard to verify, and the calculation methods of soil arch effect are various and cannot be unified. The assumption of 'soil arch' restricts the development of soil arch effect theory. This paper analyzes the characteristics of stress transfer of granular structure, and puts forward the new view that the stress spreading effect is the basic character of stress distribution in the soil body. Based on the stress having the law of automatic concentrating and balancing with strong support surface within the spreading range, the stress concentration effect still exists in the soil body.The soil arch effect will produce when the stress concentrating phenomenon overlaps in soil body. The stress concentration effect at pile top covers the whole embankment surface, and the embankment will show the typical stress distribution phenomenon of soil arch effect after the filling in pile-supported embankment exceeds the equal deposit surface height ho. The soil arch effect is the stress transfer phenomenon of soil body shear strength through the stress spreading realization. The soil arch does not exist in soil arch effect. The soil stress concentration effect and soil arch effect are all deriving effect of soil stress spreading effect. The article puts forward the general formula of calculating the equal deposit surface height ho in pile-supported embankment. The equal deposit surface height ho is related not only to the clearance of pile, but also to the property of filling.

关 键 词：土拱效应 应力扩散效应 应力集中效应 颗粒接触 应力分布 扩散角 桩承式路堤 等沉面 

分 类 号：TU43[建筑科学—岩土工程]