疏排桩在土钉墙支护基坑中的加固效果试验研究

Experimental Study on Supporting Effect of Scattered Row Piles in Soil Nailing Wall for Foundation Pit Protection

采用同济大学中型岩土离心机,进行了6组疏排桩-土钉墙组合支护基坑的离心机模型试验。基于离心机模型试验结果,探讨了疏排桩在土钉墙支护基坑中的支护效果。研究结果表明:在土钉墙支护基坑中设置疏排桩,能有效减小支护结构地表沉降,桩间距越小时,支护结构地表沉降值也越小;设置疏排桩能显著改善土钉墙变形过大的缺点,桩间距越小时,支护结构的侧向变形也越小;设置疏排桩不仅能提高支护结构的稳定性,还能改变支护结构的破坏模式。在土钉墙支护基坑中,设置疏排桩后支护结构的破坏模式主要表现为3种形态。

With medium-sized geotechnical centrifuge of Tongji University, six sets of centrifuge model test for combination of scattered row piles and soil nailing wall as foundation pit support were carried out. Based on the test results, the supporting effect of such scattered row piles was explored. The study result shows that the setting of scattered row piles in soil nailing wall as foundation pit support may effectively reduce the surface subsidence of the supporting structure to the extent that the smaller the pile spacing, the smaller the surface subsidence; the scattered row piles may improve the defect of oversize deformation of soil nailing wall significantly so that the side deformation of the supporting structure decreases as the pile spacing decreases; hence the setting of scattered row piles may not only improve stability of the supporting structure, but also change its failure mode, in that the failure mode mainly presents in three forms.