钻孔灌注桩单桩承载性状的试验研究

Experimental Study on Bearing Behavior of Single Bored Pile

利用单桩竖向抗压载荷试验,对比分析未压浆和压浆的钻孔灌注桩单桩承载性能。结果表明:在极限荷载作用下,与未压浆钻孔灌注桩的桩顶位移相比,压浆后的钻孔灌注桩的桩顶位移降幅达到57.1%;卸载至0时,与未压浆钻孔灌注桩的桩顶位移相比,压浆后钻孔灌注桩的桩顶位移降幅达到67.9%;对于所有的钻孔灌注桩而言,其桩身轴力随着深度的增加而降低。当桩顶荷载较小时,桩身轴力-深度曲线相对较陡,随着桩顶荷载的增加,曲线开始渐渐变缓。桩顶荷载越大,桩端阻力占桩顶荷载的比例越高。极限荷载作用下,压浆后钻孔灌注桩的桩端阻力明显提升,增幅达到约50%;桩端阻力占比均小于25%。

Based on the vertical compressive load test of a single pile,the bearing capacity of a single bored pile without grouting and a single bored pile with grouting was compared and analyzed.The results show that under the ultimate load,the displacement of the pile top of the bored pile after grouting is reduced by 57.1%compared with that of the pile without grouting.When unloaded to 0,the top displacement of bored pile after grouting is reduced by 67.9%compared with that of unpressed bored pile.For all bored piles,the axial force decreases with increasing depth.When the pile top load is small,the axial force-depth curve of the pile body is relatively steep,and the curve gradually slows down with the increase of pile top load.The larger the pile top load is,the higher the ratio of pile tip resistance to pile top load is.Under the ultimate load,the end resistance of the bored pile increases obviously,and the increase is about 50%.The ratio of pile end resistance is less than 25%.