加筋碎石桩加固砂土路堤边坡的试验研究

Experimental study on performance of sandy slope reinforced by geosynthetic-encased stone column

加筋碎石桩作为新型桩体被广泛用于路基加固领域,然而在路堤边坡加固或快速修复方面很少涉及。基于模型试验综合研究了加筋碎石桩桩位、桩长、桩的数量和加筋土工布类型等因素对其加固边坡效果的影响。试验结果表明:采用单根桩时,当加筋碎石桩距坡脚水平距离为0.6 H(H为坡高)和桩长为0.75 H时,其加固路堤边坡的效果最佳;相同宽度坡面时增加加筋碎石桩数量,可使边坡坡体极限承载力明显增加,而且当桩数相同时,采用抗拉强度高的土工布加筋碎石桩时边坡加固效果更加显著,且控制沉降效果更明显;对相同尺寸边坡,边坡极限荷载下加筋碎石桩变形后桩身与竖向的夹角随桩长增加而增大;坡面水平位移在坡顶和坡脚附近大,而坡面靠近加筋碎石桩桩顶附近的水平位移较小,表明加筋碎石桩可有效控制坡面上桩顶附近土体的水平变形。

Geosynthetics-encased stone columns(GESCs),a new type of column,have been widely applied in the field of ground improvement,however,it is rarely used in slope reinforcement or fast slope maintenance.Therefore,comprehensive laboratory model tests under consideration on effects of location,length,number of GESCs as well as GESCs distribution and types of geotextiles on slope reinforcement were carried out.The tests results showed that when single GESC is used in slope reinforcement,the optimum distance of column is 0.6H from slope toe,with length of 0.75H(H,slope height);for equal slope width,increasing GESCs can remarkably increase ultimate bearing capacity of the reinforced slope,for the same number of GESCs,the slope reinforcement effect with stronger geotextiles is more remarkable with higher bearing capacity compared to lower tensile geotextile;for the same size slope,after deformation occurrence under ultimate bearing capacity,the inclination angle between GESCs and vertical direction increases with the length of GESC.Horizontal displacements of slope surface near slope top and slope toe were larger,while smaller horizontal displacement were found at slope surface near the GESC top,which illustrates that geosynthetics-encased stone column can effectively control horizontal displacements around top of GESCs.