不同桩长预应力混凝土管桩承载特性对比试验

Comparative Experiment on Bearing Characteristics of Prestressed Concrete Pipe Pile with Different Pile Lengths

通过对某工程桩身埋设应力计的预应力管桩进行静荷载试验,得到不同深度处地层的桩身轴力、侧阻力和端阻力,该文分析了不同桩长桩侧阻力、桩端阻力的发挥规律,对单桩承载力实测值与规范推荐值进行对比分析。研究表明,天津非软土场地预应力管桩桩端阻力和桩侧阻力所分担桩顶荷载的比例值一般为15%和85%,桩侧阻力取值对地表以下8~16d范围内的地基土,按规范查表所得值宜按0.6~0.7的系数折减,对于深部土层宜按1.3~1.6的系数提高;对桩端阻力,当持力层为粉质黏土、黏土时,应对规范查表值折减,折减系数可取0.8~0.9;当持力层为粉土、粉砂时,应对规范查表值适当提高,提高系数可取1.1~1.2。

Through the static load test of the prestressed pipe with a stress gauge embedded in pile of a project,the axial force,side resistance and end resistance of the pile at different depths are obtained.In this paper,the development law of the side resistance and end resistance of the pile with different length is analyzed,the measured value of the bearing capacity of the single pile and the value recommended by the code are compared and analyzed.The research shows that the proportion of pile top load shared by prestressed tubular pile tip resistance and pile side resistance in the non-soft soil site in Tianjin is about 15%and 85%,and for the foundation soil within 8~16d below the surface,the pile side resistance value according to the code should be reduced by the coefficient of 0.6~0.7,and for the deep soil layer,it should be increased by the coefficient of 1.3~1.6;for the pile end resistance when the bearing layer is silty clay or clay,the standard check table value should be reduced,the reduction coefficient should be 0.8~0.9;for silt or silty sand,the standard check table value should be appropriately increased,the increase coefficient should be 1.1~1.2.