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在抗滑桩内力与变形计算中,当前理论分析多将滑床岩体等效成均质体或水平的非均质体,而三峡库区大部分滑床多为复合倾斜岩体。通过3DEC数值试验,研究了抗滑桩的有效影响范围与桩截面宽度、深度的关系,确定了抗滑桩有效影响范围的上、下限;利用面积等效,在桩的有效影响范围内提出了滑床复合倾斜岩体综合地基系数K_(Zi)的公式;推导了基于K_(Zi)的弹性抗滑桩嵌固段受力特征研究的计算公式并编写了MATLAB计算程序。以马家沟滑坡为例,采用等效法、水平层状地基系数法和基于K_(Zi)的计算方法分别进行了抗滑桩嵌固段内力、位移的计算。结果表明,基于K_(Zi)的计算方法与水平层状地基系数法相比,滑面处位移增大14.6%,内力相差较小;同时,基于K_(Zi)的计算方法根据滑动面处的位移反求桩顶的位移与现场监测位移较为接近,而利用传统方法计算位移偏小,设计偏于危险。该方法可为复合倾斜岩体地区的抗滑桩设计提供理论支撑。
In the calculation of internal forces and deformations of anti-slide piles, the current theoretical analysis mostly equates the bedrock rock mass into a homogeneous body or a horizontal heterogeneous body, whereas most of the slip beds in the Three Gorges reservoir area are mostly composite inclined rock mass. Through the 3DEC numerical experiment, the relationship between the effective range of anti-slide pile and the width and depth of the pile section is studied, and the upper and lower limits of the effective range of the anti-slide pile are determined. Using the area equivalent, the effective range of the pile is proposed Formula of composite foundation coefficient K_ (Zi) of sliding bed composite inclined rock mass; the calculation formula of the force characteristics of the elastic sliding anti-slide pile based on K_ (Zi) is deduced and the MATLAB calculation program is compiled. Taking Majiagou landslide as an example, the calculation of internal forces and displacements of the anti-slide piles are respectively carried out by the equivalent method, the horizontal layered foundation coefficient method and the calculation method based on K_ (Zi). The results show that the calculation method based on K_ (Zi) is 14.6% larger than that of horizontal layered soil foundation method, and the difference of internal forces is small. At the same time, the calculation method based on K_ (Zi) The displacement of reverse top is close to that of on-site monitoring, while the traditional method is used to calculate the small displacement and the design is dangerous. The method can provide theoretical support for the design of anti-slide piles in composite inclined rock mass area.