深基坑双排支护桩随机有限杆单元法的计算研究

Calculation and research of stochastic finite bar element method in double-row retaining piles

将双排支护桩当作框架结构考虑,提出了新的m法理论,将坑底以上前后排桩土产生的作用在前排桩坑底以下桩后的土压力及单排桩坑底以下桩后的土压力考虑在桩的受力中。双排桩及单排桩受到的土压力为位移、排桩净距和土性指标等的函数。用室内模型试验、新的m法理论及双排桩随机有限杆单元法得出:桩顶连梁与桩的刚度比达到一定值时,再继续增加连梁刚度无意义;按照公路铁路规范确定的排桩间不相互影响的排桩净距值偏于保守。跟上部结构一样,岩土概率法的发展方向不可逆转。

The double-row retaining piles were considered into a frame construction,and the new m method was proposed.The new m method is that the coordinate origin of front row pile of double-row piles(or the single-row pile) is marked on the bottom of pit,and consider the earth pressure on the back of front-row pile(or single-row pile) below the bottom of pit which is caused by the gravity of soil above the pit bottom into the differential equation of pile.The earth pressure of single-row pile and double-row piles is the function of pile displacement and net distance between the double-row piles and the engineering characters of the soils.Through the model test indoor and the new m method theory and the stochastic finite bar element method,the following conclusions were gained: when the rigidity ratio of the pile and the top girder is not less than some value and continue to increase this rigidity ratio do not have any biggish benefit;the net distance in the bridge criterions between the double-row piles which do not influence each other is some more than the practice.As same as engineering structure,the probability method is the way of development of the remaining pile,which can not be changed.