基于修正计算宽度的斜坡场地m值取值方法研究

Research on the Accessor Method of m Value on Slope Site Based on the Modified Calculative Width

地形坡度是地基抗力系数比例系数m值的主要影响因素之一,现有规范经验对斜坡场地m值取值研究极少。笔者进行3种坡度下的单桩水平载荷现场试验,通过m法对桩身变形、内力进行验算和等效调整以及数值模拟验证,研究了斜坡场地m值取值问题。试验研究及理论计算表明:①m法理论计算得到桩身中部的水平位移和弯矩明显小于斜坡场地现场试验实测值,位移零点和弯矩最大值位置均高于实测值;②将斜坡场地等效为土体强度降低后的水平场地,得到斜坡场地实际m值大于直接引用规范公式的计算值,且随坡度的增大二者差异越大;③桩身计算宽度是造成斜坡场地实际m值与规范公式计算值的差异来源,随着坡度的增大实际桩身计算宽度呈线性减小;④通过修正桩身计算宽度,提出基于规范公式的斜坡场地m值修正公式。

The slope gradient is one of the main factors influencing the proportionality coefficient of horizontal resistance coefficient of foundation,namely m value. However there are rarely study of m value on slope site in the existing norms and experience. In this paper,horizontal static load test of single pile with different slope gradient were designed and carried out. By m method calculating,displacement and bending momentof pile were checked,then according to the equivalent adjustment,the m value on slope site was researched,and verified by numerical simulation. The experimental study and theoretical calculation show that: First,horizontal displacement and bending moment in the middle of pile calculated by m method are much smaller than measured values,and the position of the zero displacement and the maximum bending moment were higher than the measured values. Second,the slope was equivalent to horizontal ground whose soil strength is reduced,then it showed thatthe actual m value on the slope was greater than the calculated value referenced directly,and the difference is larger with the increase of slope. Third,pile calculated width was the reason for the difference between the actual m values and ones came fromstandard formula,and the actual calculative width was a linear decrease with the increase of slope. Fourth,through correcting thecalculative width,the correction formula for determining them value on the slopebased on the standard formula was put forward.