论文部分内容阅读
评价抗隆起稳定性是软土基坑支护设计中一项重要工作.传统的安全系数法无法考虑到岩土参数不确定性对抗隆起稳定的影响,为此基于可靠度理论,以土体参数γ、c、φ为随机变量,利用改进的一次二阶矩法计算软土基坑抗隆起稳定可靠性指标.通过基坑工程实例,分别采用可靠度和安全系数法评价了基坑抗隆起稳定性,分析了土性指标的均值和变异性对基坑抗隆起稳定可靠指标的影响.结果表明,采用改进的一次二阶矩可靠度计算方法评价基坑抗隆起稳定性具有科学性和合理性,基坑抗隆起稳定可靠指标β对参数均值变化的敏感性明显大于安全系数Fs.土性指标φ的变异性对基坑抗隆起稳定可靠指标β的影响最大,c的变异性影响次之,γ的变异性对β的影响最小.
The evaluation of anti-uplift stability is an important task in soft soil foundation pit support design. The traditional safety factor method cannot take into account the influence of rock and soil parameter uncertainty on the stability of the uplift. Therefore, based on the reliability theory, the soil parameters are used. γ, c, φ are random variables. The improved first-order second-moment method is used to calculate the stability reliability index of anti-uplift in soft soil foundation pits. Through the example of excavation engineering, the reliability and safety factor method are used to evaluate the anti-peak uplift stability. Sex, analyzes the influence of mean and variability of soil indexes on the stability and reliability index of anti-uplift of foundation pits. The results show that it is scientific and rational to evaluate the stability of foundation pit anti-uplift using the improved first-order second moment reliability calculation method. The sensitivity of the stability and reliability index β of the anti-uplift of the foundation pit to the change of the parameter mean is obviously greater than the safety factor Fs. The variability of the earthness index φ has the greatest influence on the stability and reliability index β of the anti-uplift of the foundation pit, and the effect of the variation of the c is the second. The variability of γ has minimal effect on β.