地下水和空间土拱效应作用下深大圆形基坑非极限主动土压力分布研究

Study on Non-limit Active Earth Pressure Distribution of Deep Large Circular Excavations Considering Groundwater and Spatial Soil Arching Effects

  • 摘要: 在深大圆形基坑应用日益广泛的背景下,发展能够综合考虑复杂因素的土压力计算方法,对于提升设计的精细化和科学化水平具有重要的工程实践价值。鉴于此,提出一种考虑地下水作用、空间拱效应及墙体位移模式的圆形基坑非极限主动土压力求解方法,并通过工程实例验证了该方法的适用性与有效性。在此基础上,进一步分析土体参数、墙体位移模式、地面超载及地下水位对土压力分布的影响规律。研究结果表明:圆形基坑的土压力随深度的增加呈先增加后减小的趋势,受空间拱效应影响,其土压力显著小于传统朗肯土压力计算值;土压力与土体黏聚力、内摩擦角均呈负相关关系;邻近地表超载会在墙体上方产生附加土压力,该附加土压力随埋深增加而减小;地下水位越低、墙体位移量越大,位移区域越广,主动土压力的衰减就越显著。

     

    Abstract: With the increasing application of deep and large circular excavations, developing an earth pressure evaluation method that comprehensively accounts for complex influencing factors is of significant engineering value for enhancing design accuracy and scientific reliability. In this study, a non-limit active earth pressure calculation method for circular excavations is proposed, which incorporates groundwater effects, spatial arching effects, and wall displacement patterns. The applicability and effectiveness of the method are validated through an engineering case study. Furthermore, the influences of soil parameters, wall displacement patterns, surface surcharge, and groundwater level on earth pressure distribution are investigated. The results show that the earth pressure in circular excavations first increases and then decreases with depth, and due to spatial arching effects, it is significantly lower than the traditional Rankine earth pressure estimation. The earth pressure is negatively correlated with soil cohesion and internal friction angle. Surface surcharge generates additional earth pressure on the upper portion of the wall, which decreases with depth. A lower groundwater level, larger wall displacement magnitude, and wider displacement zone result in a more significant reduction in active earth pressure.

     

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