摘要
现有关于卸荷拱的研究,基本上都没有考虑土压力随位移的变化而不断变化这一实际。首先,根据土压力随位移的非线性变化规律以及各个区域不同程度的变形,把卸荷拱周围的土压力差简化成前后为均匀分布、左右呈三角形分布的荷载形式,并对卸荷拱在此压力差作用下的力学特征进行了分析,推出了卸荷拱和平衡拱的轴线方程、跨度和矢高的计算表达式。最后,结合所划分的坑周变形区域和显著性影响范围(AIR)的定义,分析了坑周土体的弹塑性变形量随变形范围变化的累积关系,并得到了卸荷拱周围土压力差的一种简化计算方法。
The magnitude and form of unloading arch play important role in and the deformation of foundation pit. The present researches on unloading the distribution of space earth pressure arch almost ignored the nonlinear relationship earth pressure varying with displacement or deformation, which is determined in foundation pit. Firstly, some advances in mechanism analysis and calculation method of soil arch effect were reviewed. Secondly, the area around foundation pit are divided into un-touch area, elasticity area, plasticity area, destroy area four parts by different deformation after foundation pit is excavated. Combined with the mechanism of soil arch, the developmental mechanism of unloading arch and balance arch in foundation pit was analyzed. Thirdly, the progress and status of studies on nonlinear relationship of earth pressure varying with the displacement in foundation pit were summarized. Then, considering the nonlinear relationship between earth pressure and displacement, the earth pressure difference acting on unloading arch was simplified as uniform distribution on both sides of the front and back, triangle distribu, tion on both sides of the left and right. And the formula of the axis, span and height of unloading arch and balance arch are put forward by analyzing mechanics characteristic and deformation law of unloading arch in foundation pit. Finally, based on the concept of AIR and the different deformation of elasticity area and plasticity area, the rule on the deformation varying with the distance was analyzed. And the calculation method of earth pressure difference was obtained. The soil arch effect in foundation pit can be reckoned and analyzed through the earth pressure difference and the calculating methods on axis, span and high of unloading arch and balance arch.
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2008年第6期27-31,共5页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
国家自然科学基金资助项目(40872205)
全国高等学校博士学科专项科研基金资助项目(20070558032)
广东省自然科学基金资助项目(07003738)
广东省科技计划资助项目(2008B030303009
2003C33301)
关键词
基坑
卸荷拱
土拱
土压力
位移
foundation pit
unloading arch
soil arch
earth pressure
displacement
