土钉支护结构可靠度分析的电子表格法

Reliability analysis of soil nailed structures using spreadsheet method

岩土工程中存在大量的不确定性,因此,进行土钉支护结构的可靠度分析是十分必要的。利用Excel的规划求解及VB编程功能,采用电子表格法,建立了适用于分层土体的电子表格计算模型,进行了土钉支护结构内部稳定的可靠度分析,得出了最小可靠指标及其相应的临界滑面位置。建立的电子表格模型由数据输入模块、土钉计算模块、土层计算模块、可靠指标计算模块及优化求解模块5部分组成。模型建立之后,只需改变电子表格中的输入数据,即可适用于不同土钉支护结构的可靠度分析。算例分析表明:方法正确,计算过程简单直观。它既可用于不同工况下土钉支护结构内部稳定的可靠度分析,也可简化为相应情况下的定值法分析。

It is very important to carry out the reliability analysis of soil nailed structures since there are lots of uncertainties in geotechnical engineering. Considering the function of Solver and VB programming of Excel, the spreadsheet computation model for the reliability analysis of soil nailed structures is set up. This spreadsheet model is suitable for layered soils and it can get the minimum reliability index and the location of the corresponding slip surface. The spreadsheet model is composed of five parts： module of input parameters; computation module of soil nailed structure; computation module of soil layers; computation module of reliability index and module of optimum calculation. Once the model is set up, it is very convenient to carry out the reliability analysis for different soil nailed structures. It is demonstrated that the method proposed is correct, simple and direct. It is easy to carry out the reliability analysis of soil nailed structures for different computation cases; and it can also be easily simplified to carry out the corresponding deterministic analysis.