黄河流域冲积层本构模型的深基坑适用性研究

以沿黄河流域不同地区地质力学特征差异较大的3种类别基坑为工程背景，分析所甄选的5种本构模型各自的屈服特征及适用条件，结合厚冲积层典型流域的地质力学参数特征，采用有限差分法模拟软件二次开发平台及实测数据，研究了各自区域基坑开挖结构变形所匹配的本构模型。研究表明：沿黄河冲积流域线，地质力学特征出现较大差异，总体上来说东部颗粒级配较好，西部地层深处以未固结的粘土和细砂为主；简尼模型能较为准确模拟济南基坑围护桩变形特征，邓肯张模型可表征该地区基坑地表的沉降变化发展规律；摩尔库伦模型在拟合郑州地区主动土压力时具有较高的精准性；修正剑桥模型在跟踪兰州地区基坑锚索轴力随时间变化的轨迹时与实测数据较为吻合。

Suitable constitutive model of pit in thick alluvial clay along Huanghe River

In view of three types of foundation pit in the Huanghe River basin with different geo-mechanical characteristics, this paper aims to explore the yield behaviour and application conditions of five prescribed constitutive models. Combing geo-mechanical parameter characteristics in typical area of thick alluvium, the constitutive model matching structural deformation of foundation pit excavation in respective area, by employing secondary development platform of finite difference method simulation software as well as field test data. Results show that:geo-mechanical characteristics varies significantly along the Huanghe River alluvium. Generally, the eastern stratum shows well grain size gradation, while the deep western stratum is mainly consist of unconsolidated clay and fine sand. The deformation behaviour of retaining pile for foundation pit in Jinan can be precisely simulated by Jene model, and meanwhile, the law of foundation pit surface deformation development can be described by Duncan Chang model. M-C model fits the active earth pressure with high accuracy in Zhengzhou, the time-dependent change law of axial force simulated by modified Cambridge model is in good accordance with the field test data.