STUDY ON BEARING CAPACITY OF FOUNDATIONS OF SATURATED GRAVELLY SOIL IN THE RESERVOIR ZONE OF THE CHANGJIANG GORGES
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摘要: 三峡库区表层是第四系松散堆积体,碎、砾石含量一般在30%~70%。三峡水库蓄水以后,原来在天然状态下的碎石土地基将会受到水的浸泡而饱和,从而导致其承载力下降,但现行的《公路桥涵地基与基础设计规范》(JTJ02485)并没有给出饱和状态下碎石土地基的承载力,这给蓄水后碎石土地基的承载力的复核与评估带来了极大不便。为解决这一问题,首先对库区典型的碎石土在天然及饱和状态下的抗剪强度指标进行了试验研究,得到了碎石土的粘聚力和内摩擦角在天然及饱和状态下的变化规律。依据试验结果,采用碎石土地基承载力的经典计算公式,即地基极限承载力的Bell解,对桥基饱水后承载力进行折减,结合规范给出了饱和碎石土地基的承载力值,为蓄水后公路与桥梁的碎石土地基的承载力复核与评估提供了可靠依据。Abstract: The surface layer of the stratum in the Reservoir Zone of the Changjiang Gorges( RZCG) is loose deposits, The gravel content of gravelly soils in this region ranges from 30% to 70% .Storage of water in the RZCG is not taken into consideration when roads are being built.The gravelly soil foundation under inundation will be saturated, which will lead to the loss of its bearing capacity.Unfortunately, the standard currently in effect Specifications for Design of Ground Base and Foundation of Highway Bridges and Culverts ( JTJ 024- 85) , doesn't offer the values of the bearing capacity for saturated gravelly soil, which will bring inconvenience to the recheck and evaluation of the bearing capacity of saturated gravelly soil foundations.To solve the problem, experimental study is carried out firstly.Shear strength indexes of gravelly soil were tested under natural and saturated conditions, and the Laws of the development of cohesion and internal friction of gravelly soil are obtained.Based on testing results, the bearing capacity of the foundation of saturated gravelly soil are offered through a traditional formula for bearing capacity of gravelly soil, namley Bell solution of ultimate bearing capacity.The achievement provides reliable confidence to the recheck and evaluation of bearing capacity of gravelly soil foundations when water storage is done.
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Key words:
- bearing capacity of foundations /
- gravelly soil /
- saturation RZCG /
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