抗滑桩计算的确定性计算模型

现有抗滑桩力学计算模型中锚固段采用弹性地基梁,滑坡推力的大小通过计算确定,这二者都是确定的,而滑坡推力的分布形式则采用某种理想形式,包含较多的不确定因素。以定点剪出稳定性核算为基础,提出滑坡推力分布形式分析计算方法,该法假定自指定点剪出的潜在滑面由坡体中通过指定剪出点的圆弧滑面或部分原滑坡滑面与圆弧面组合而成,按照反力法计算设计滑坡推力,桩前土体考虑设计安全系数并按照相同的方法确定抗力。获得全桩若干点处的计算结果以后,可以得到相邻两点间的坡体压力增量,据此按照自上而下的次序确定桩身坡体压力的分布形式。在此基础上建立的抗滑桩计算模型,各种条件皆可通过计算确定,为一种确定性计算模型。

A DETERMINISTIC COMPUTATIONAL MODEL OF THE ANTI-SLIDE PILES

In present computational model of the anti-slide pile,the anchoring segment is assumed as elastic foundation beam,and the quantitative of the landslide thrust can be calculated.So,these two computational conditions are deterministic.But the distributions of landslide thrust on anti-slide pile are approximately determined to be in shapes of triangle,rectangle,or echelon,solely based on rock characters of the gliding mass.In this article,a new method is proposed to improve the calculation of distribution forms according to stability of the gliding mass sliding through the specified shear opening.It is assumed that the potential slide surface is composed of a part of the original slide surface and a circular surface through the specified shear opening.If this safety factor of the specified shear opening is less than the design one,then the landslide thrust of the corresponding slide surface is calculated.The shear openings are specified at the pile from top to bottom by a certain interval.By this method,the landslide thrust at many points of the pile can be calculated.The increment of landslide thrust of the section between two adjacent shear openings can be obtained by comparing the landslide thrust of adjacent shear openings.So,the distribution forms of landslide thrust of the pile from top to bottom can be determined.As far as the sliding mass forward the pile, it can supply resistance force only when its safety factor is bigger than the design one,and its distribution law can be calculated by the same method as that of the landslide thrust.Based on all the calculation,a deterministic computational model of the anti-slide pile can be established.