黄土地基湿陷变形的试验研究

The Experimental Study on the Regularities of Collapsible Deformation of Loess Foundation

为进一步探索晋南黄土地基的自重湿陷和外荷湿陷变形规律,在山西河津山西铝厂霞光生活区进行了大量的室内外试验,包括三个大面积试坑浸水试验和天然地基及强夯地基的三个浸水载荷试验。试坑浸水试验结果表明,原勘察报告对场地湿陷类型的判定有误,应为非自重湿陷性场地;详细讨论了自重和外荷湿陷变形的规律;探讨了《78黄土规范》中有关湿陷性黄土场地类型的评判方法。并提出了调整系数m_0;采用模糊数学方法,对自重湿陷敏感性进行了综合评判,并提出了评判指标β和分档标准,试验及计算简便,可靠度达92%;通过非线性有限元分析,湿陷量的计算值与实测值比较接近,并在计算外荷湿陷量的有限元计算中采用了模糊数学方法求取各分层土的参数。

In order to discuss the deformation characteristics of collapsible loess foundation in South Shanxi, a lot of laboratory and in-situ tests are carried out, which include three in-situ ponding tests and three in-situ ponding plate loading tests, The results of in-situ ponding tests show that the type of collapsibility of the site in prospecting report is erroneous and the site should be non-self-subsiding. The regularities of collapsible deformation of loess foundation and the evaluation of the type of collapsibility suggested in the Chinese Regulation on Building Construction in Region of Collapsible Loess (TJ25-78) are discussed and a coefficient m_0is suggested to modify the original formula. By using fuzzy mathematics, a synthetic judgement for sensitivity to self-subsidence is given, and an index as well as the sensitivity criterion is also proposed. This method is easy and has high reliability. The collapsible deformation of collapsible loess foundation is calculated by non-linear finite element method. The calculated values are quite approximate to the measured values. Of each layer in finite element analysis fuzzy method is used in seeking the parameters.