复杂环境下某深厚软土基坑的实测性状研究
发布时间：2018-08-17 16:03
【摘要】：详尽分析了杭州某上部带有较厚硬壳层的深厚软黏土地基中,开挖深度为17.4~19.8 m,采用地下连续墙和多层钢筋混凝土支撑作为支护结构的超深基坑工程的实测性状。现场监测内容包括基坑侧壁土体水平位移、坑外地表沉降及内支撑轴力。研究表明,本案例基坑的最大水平位移与基坑最大开挖深度之比hm m?/H介于0.24%~0.75%,最大水平位移超过100 mm,其中蠕变变形占总侧向变形的比例高达44%~56%,基坑水平位移蠕变速率为0.15~0.76 mm/d,蠕变速率与基坑开挖深度和基底附近土层性质有密切关系;"T"型地下连续墙和隔断墙技术对减小侧壁土体变形有一定作用。基坑坑外横向地面沉降大致呈抛物线分布,坑外纵向沉降大致呈马鞍形,地表周围土体最大沉降与基坑最大开挖深度之比vm m?/H介于0.26%~0.7%,最大沉降量与坑壁最大侧向位移量的关系大致为vmax hmax???~hmax2.57?,沉降蠕变速率为0.1~0.6 mm/d。随着开挖及相邻支撑的浇筑及拆除,多层支撑支护结构中各层支撑的轴力不断变化。
[Abstract]:In this paper, a deep soft clay foundation with a thick hard shell layer in the upper part of Hangzhou is analyzed in detail. The excavation depth is 17.4 ~ 19.8 m.The underground continuous wall and multi-story reinforced concrete brace are used as the support structure for the measured behavior of ultra-deep foundation pit engineering. Field monitoring includes horizontal displacement of lateral soil, surface settlement and axial force of inner support. Research shows that In this case, the ratio of the maximum horizontal displacement to the maximum excavation depth of the foundation pit is between 0.24 mm and 0.75 mm, and the maximum horizontal displacement is more than 100 mm, in which the proportion of creep deformation to total lateral deformation is as high as 44 / 56.The creep rate of horizontal displacement of foundation pit is 0.150.76 mm / d, compacted with vermicelli. The rate of variation is closely related to the excavation depth of foundation pit and the properties of soil layer near the foundation, and the technology of "T" type underground continuous wall and partition wall plays a certain role in reducing the deformation of lateral wall soil. The lateral ground settlement outside the pit is approximately parabola distribution, and the longitudinal settlement outside the pit is approximately saddle-shaped. The ratio between the maximum settlement of soil around the surface and the maximum excavation depth of foundation pit is between 0.260.0.The relationship between the maximum settlement and the maximum lateral displacement of the pit wall is approximately 2.57g / h, and the creep rate of settlement is 0.1 ~ 0.6mm / d. With the excavation and the pouring and dismantling of adjacent braces, the axial forces of each layer of multi-layer bracing structure are constantly changing.
【作者单位】： 浙江大学滨海和城市岩土工程研究中心;浙江大学软弱土与环境土工教育部重点实验室;杭州运河集团投资发展有限公司;浙江省建筑设计研究院;
【基金】：国家自然科学基金项目(51278462) 浙江省建设厅科技推广应用研究项目
【分类号】：TU433
[Abstract]:In this paper, a deep soft clay foundation with a thick hard shell layer in the upper part of Hangzhou is analyzed in detail. The excavation depth is 17.4 ~ 19.8 m.The underground continuous wall and multi-story reinforced concrete brace are used as the support structure for the measured behavior of ultra-deep foundation pit engineering. Field monitoring includes horizontal displacement of lateral soil, surface settlement and axial force of inner support. Research shows that In this case, the ratio of the maximum horizontal displacement to the maximum excavation depth of the foundation pit is between 0.24 mm and 0.75 mm, and the maximum horizontal displacement is more than 100 mm, in which the proportion of creep deformation to total lateral deformation is as high as 44 / 56.The creep rate of horizontal displacement of foundation pit is 0.150.76 mm / d, compacted with vermicelli. The rate of variation is closely related to the excavation depth of foundation pit and the properties of soil layer near the foundation, and the technology of "T" type underground continuous wall and partition wall plays a certain role in reducing the deformation of lateral wall soil. The lateral ground settlement outside the pit is approximately parabola distribution, and the longitudinal settlement outside the pit is approximately saddle-shaped. The ratio between the maximum settlement of soil around the surface and the maximum excavation depth of foundation pit is between 0.260.0.The relationship between the maximum settlement and the maximum lateral displacement of the pit wall is approximately 2.57g / h, and the creep rate of settlement is 0.1 ~ 0.6mm / d. With the excavation and the pouring and dismantling of adjacent braces, the axial forces of each layer of multi-layer bracing structure are constantly changing.
【作者单位】： 浙江大学滨海和城市岩土工程研究中心;浙江大学软弱土与环境土工教育部重点实验室;杭州运河集团投资发展有限公司;浙江省建筑设计研究院;
【基金】：国家自然科学基金项目(51278462) 浙江省建设厅科技推广应用研究项目
【分类号】：TU433
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