碎石土及碎石土-基岩地基斜坡场地m值研究

四川山区输电线路常在陡峻斜坡走线，碎石土、基岩二元结构地层分布普遍。针对此类场地和地基，斜坡桩基水平抗力系数的比例系数m值取值是陡峻边坡输电线路铁塔桩基设计中亟待解决的问题。根据单桩水平静载试验获取m值，采取现场试验、室内模型试验、数值模拟3种方法进行综合分析，研究了陡峻边坡碎石土、碎石土-基岩地基基桩水平作用力参数m值的变化规律、影响因素及取值。得出以下结论：斜坡场地m值随坡度的增大呈线性减小，且碎石土地基减小幅度大于碎石土-基岩地基；对m值影响程度最重要的因素依次为场地坡度、土体密实度、桩长、桩径；提出陡峻边坡碎石土、碎石土-基岩场地考虑以上重要影响因子的m值估算公式，并给出了修正系数。

Determination of coefficient m for foundation on a gravel soil-bedrock slope

Transmission line in Sichuan mountainous area always layout in steep slope, where Gravel soil and bedrock dual structure formation are common in the region. As such, proportional coefficient m of ground horizontal resistance coefficient is the problems to be settled urgently in the design of transmission line tower pile foundation in the steep slope. m value is obtained by the static horizontal loading test of single pile. Three methods including field experiment, indoor model test, and numerical simulation are used to investigate the changing rules, influence factors and accessor methods of the m value. The results indicate m value of slope site decreases linearly with the increase of slope, and the decrease of m in gravel soil is greater than in the gravel soil-bedrock foundation. The most influencing factors on m value are ground slope, soil compactness, pile length and pile diameter. The proposed prediction formula considers impact factors of m value of the gravel soil, gravel soil and bedrock in slope site, and provides the correction coefficient.