多因素复杂参数下的圆形地下水泥土桩地基场地地震效应分析
Seismic Site Effect of Circular Underground Cement—Soil Pile Foundation Considering Multi-factor and Complex Parameters

为了实现圆形地下水泥土桩地基场地地震效应的准确分析，提高建筑抗震性能，采用ABAQUS有限元软件，分析不同随机参数的圆形地下水泥土桩地基场地地震效应，分析运算采用的各项参数、场地地质条件以及明确等效复合土体计算参数，通过二维复合模量简化模型，全面考虑加固深度、土桩地基上新建结构、下卧基岩地形、水泥土模量、输入地震波属性和不同场景环境等随机参数对圆形地下水泥土桩地基场地地震效应的影响。实验结果表明：圆形地下水泥土桩地基加固区地表的峰值加速度反应较自由场的反应显著降低，地基地表的峰值加速度反应随着水泥土桩加固深度和复合模量的增加而减小；地基上新建结构对坝基周围场地地震动特性形成较强的干扰，干扰幅度以及区域同新建结构规模具有较高的关联性；地基下端基岩表面地形同上部地基场地地震动特性间具有一定的关联性；场地土层条件对复合地基地震效应影响较大；桩体模量在可能变化范围内，对水泥土桩地基地震效应影响相对较小。
To accurately analyze the seismic site effect of circular underground cement—soil pile foundations and improve the seismic performance of buildings, in this study, we used ABAQUS finite element software to analyze the seismic effect on circular underground cement—soil pile foundations with different random parameters. Specifically, we analyzed the parameters used in the calculation, the geological conditions of the site, and the equivalent composite soil parameters. Using a simplified model of a two-dimensional composite modulus, we discuss the influences of the reinforcement depth, a newly built structure on the foundation, the topography of the underlying bedrock, and some random parameters (e.g., modulus of cement soil, seismic attributes, and different scenes) on the seismic site effect. The experimental results show that the peak acceleration response on the circular underground cement—soil pile foundation decreases with increased reinforcement depth of the cement—soil pile and composite modulus, and is significantly lower than that on a free field. A new structure on the foundation experiences a strong disturbance in the ground motion characteristics around the foundation, and the interference amplitude and area have a high correlation with the structure scale. We found a certain correlation between the bedrock terrain at the bottom of the foundation and the ground motion characteristics of the upper foundation. The influence of soil conditions on the seismic effect of the composite foundation is great, whereas the influence of the pile modulus is relatively small.