碎石土填方场地嵌岩桩负摩阻力性状分析

Analysis of Negative Frictional Resistance Characteristics of Rock Socketed Piles in Gravel Soil Filling Sites

以西南地区土石混合体为研究对象,通过单桩室内模型试验,研究了素填土和土石混合料地基中桩周土体沉降、桩土位移、桩身轴力、桩侧负摩阻力、中性点位置等。结果表明:土石混合料填土地基中桩周土体与桩身沉降较素填土地基中更小;在堆载及加载作用下,中性点位置随着荷载等级提高而下移,且土石混合料地基的中性点位置高于素填土地基,其中性点位置距桩顶0.36 l~0.52(l l为有效桩长)内;桩身轴力在土石混合料和素填土中均随深度先增后减,但土石混合料填土地基中桩身轴力小于素填土地基。

Taking the soil-rock mixture in the southwest region as the research object,single pile indoor model tests were conducted to study the settlement of the soil around the pile,displacement of the pile soil,axial force of the pile body,negative friction on the pile side,and neutral point position in the foundation of plain fill and soil-rock mixture.The results show that the settlement of the soil around the pile and the pile body in the soil filled soil foundation with soil-rock mixture is smaller than that in the plain filled soil foundation.Under the action of stacking and loading,the neutral point position moves downwards with the increase of load level,and the neutral point position of the soil-rock mixture foundation is higher than that of the plain fill foundation.The neutral point position is within 0.36 l to 0.52 l(l is the effective pile length)from the top of the pile.The axial force of the pile increases and then decreases with depth in both soil-rock mixture and plain fill,however,the axial force of the pile in soil-rock mixture filled foundation is smaller than that in plain fill foundation.