基于统一强度理论抗滑桩桩间距的计算

CALCULATION OF ANTI-SLIDE PILE SPACING BASED ON UNIFIED STRENGTH THEORY

在已有抗滑桩桩间距研究的基础上,对桩间土拱进行受力分析。从侧阻力条件和土拱强度条件两个方面对抗滑桩桩间距进行了计算,将统一强度理论引入土拱强度的分析,藉此分别判断拱顶前缘、后缘及拱脚处土体是否处于临界状态,可得3个桩间距值,取相应的最小桩间距作为设计桩间距。此方法对于滑坡推力的矩形、三角形和梯形分布形式均适用,并可考虑土体自重应力的影响,同时可推及锚索抗滑桩桩间距的计算。对两个计算实例进行了分析,本方法的计算值与已有计算值或设计值的比较表明本方法效果良好。具体计算中统一强度参数b取0.2~0.7较为合适,滑坡推力为矩形分布时b值约为0.3,滑坡推力为三角形分布时b值约为0.6,滑坡推力为梯形分布时b值介于两者之间。

Stress analysis is done to the soil arch between piles.It is based on existing research of anti-slide pile spacing.Pile spacing is calculated by two conditions.They are side resistance and soil arch strength.Unified strength theory is introduced to analyze soil arch strength.On the basis of this analysis,the front and posterior arch roof and arch foot are respectively judged that the soil is or is not in critical state.Then the values of three pile spacing can be obtained.The corresponding minimum pile spacing is taken as the design one.The method is suitable for slide thrust distribution with the form of either rectangle,or triangle or trapezoid.Soil self-weight stress can be also considered.It can be simultaneously applied to the anchored anti-slide pile spacing.Two calculation examples are analyzed by the presented method.The comparison between the calculation results and the existing or design results shows that the effect of proposed method is satisfactory.When specific calculation is done,the suitable value of unified strength parameter b is between 0.2and 0.7.When slide thrust is rectangular distribution,b is about 0.3.For triangular distribution,b is about 0.6.For trapezium distribution,b lies between 0.3and 0.6.