软土地基的变形速率及稳定性控制

发布时间：2018-03-18 22:49

本文选题：道路工程　切入点：软土　出处：《中国公路学报》2017年02期 　论文类型：期刊论文

【摘要】：为了给软土堆载工程监测提供依据,讨论了工程中常采用的沉降速率10mm·d-1、水平位移速率5mm·d-1作为各类软土地基稳定性控制指标的适用性,并研究了不同加载速率和地基处理方式对软土地基变形的影响。结合上海某工程塑料排水板地基的监测数据,研究了堆载作用下软土地基的变形速率特征,并采用有限元法详细分析了加载速率和地基处理方式(有、无塑料排水板)对软土地基变形速率的影响。研究结果表明:这种采用位移速率为控制指标的方法并不能完全准确反映地基的稳定性,在加载初期安全性较大时位移速率会超过控制标准,而在地基破坏前的位移速率却低于控制标准;加载速率对变形速率有直接影响,加载速率越大地基变形速率也越大;地基的排水性能对变形速率有显著影响,打设塑料排水板的地基比其他类型处理的地基具有更大的变形速率。此外,对于塑料排水板软土地基,软土的固结压密以及排水系统性能的弱化也会造成该类地基的变形速率呈现前期快而后期慢的反常现象。因此,对于塑料排水板软土地基的稳定性控制,这种特殊现象在地基变形监测数据分析中应该予以重视。
[Abstract]:In order to provide the basis for monitoring the soft soil surcharge engineering, the applicability of the settlement rate 10mm 路d-1 and the horizontal displacement rate 5mm 路d-1, which are often used in the engineering, as the stability control indexes of the soft soil foundation are discussed. The effects of different loading rates and foundation treatment methods on the deformation of soft soil foundation are studied. Based on the monitoring data of plastic drainage plate foundation of a Shanghai project, the deformation rate characteristics of soft soil foundation under the action of surcharge are studied. The loading rate and foundation treatment method are analyzed in detail by using finite element method. The results show that the method using displacement rate as the control index can not completely reflect the stability of the foundation. When the initial loading is safe, the displacement rate will exceed the control standard, but the displacement rate before the foundation failure is lower than the control standard, and the loading rate has a direct effect on the deformation rate, the larger the loading rate, the greater the deformation rate of the foundation. The drainage performance of the foundation has a significant effect on the deformation rate, and the foundation with the plastic drainage board has a higher deformation rate than the foundation treated by other types of treatment. In addition, for the soft soil foundation of the plastic drainage plate, The consolidation and compaction of soft soil and the weakening of drainage system will also result in the abnormal phenomenon that the deformation rate of this kind of foundation is fast in the early stage and slow in the later stage. Therefore, the stability of the soft soil foundation with plastic drainage plate is controlled. This special phenomenon should be paid more attention to in the analysis of deformation monitoring data.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;中铁二院昆明勘察设计研究院有限责任公司;
【基金】：国家自然科学基金项目(40702051)
【分类号】：U416.1

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