摘要
砂卵石地层高强度、高渗透性以及低黏聚力的力学特性使得砂卵石基坑工程安全等级划分与评价不同于一般基坑工程。为了对砂卵石基坑安全等级进行有效评价,首先选取基坑开挖深度、砂卵石层厚度及地下水位高度作为砂卵石基坑安全等级评价指标,制定砂卵石基坑安全等级划分及评价标准,然后建立砂卵石基坑本体安全等级物元可拓评价模型,采用有限元计算与层次分析相结合的方法确定指标权重,最后给出砂卵石基坑安全等级评价规范化流程。利用所建立的模型对长沙地区某砂卵石基坑工程进行评价。结果表明,所建立的物元可拓评价模型不但能够定量辨别基坑的安全等级,而且能够区分同一等级不同基坑的相对危险性。
This paper aims to bring forward our method for effective and scientific evaluation of the safety grades of the sandy cobble foundation pits. As is known, when designing or planning to set up a building or a bridge, great attention should be attached to decision-making on what depth is needed for the foundation of sandy cobble grounds, particularly in the area of Changsha, Hunan. Coming from this need, we have established a safety grade partition and the evaluation standard of the sandy cobble foundation pits, and then work out the matter-element extension evaluation model to calculate the safety degree of such sandy cobble foundations due to the need of high strength, high permeability and low cohesion mechanical properties of such sandy cobble grounds. At the same time, in order to gain the objective and scientific coefficients of the evaluation index weight, we have to combine the method of evaluation with the orthogonal experimental design, the FEM computation and analytic hierarchy process to incorporate the different evaluation index values to work out all the different engineering conditions in an integrated way. In addition, it is also necessary for us to work out the horizontal displacements of retaining wall in different engineering conditions via the FEM computation so as to obtain the judgment matrix through the multiple regression analysis and deduce the evaluation index weight coefficients via the hierarchical analysis. At the same time, we have also established the standardized safety grade evaluation method and process of the sandy cobble foundation pits, which is convenient and easy in use. And, finally, a trial application procedure has been laid out to evaluate the three sandy cobble foundation pits in Changsha with satisfactory results. Thus, the matter-element extension evaluation model we have proposed proves to be available for the safety grade evaluation of the similar sandy cobble foundation pits.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2013年第2期252-256,共5页
Journal of Safety and Environment
基金
交通部西部科技中心项目(200831875818)
关键词
安全工程
砂卵石基坑
安全等级
评价标准
物元可拓评价
有限元计算
层次分析法
safety engineering
sandy cobble foundation pits
safetygrade
evaluation standard
matter-element extension evaluation
FEM computation
AHP
