桩侧注浆结石体定量表征物理模拟试验

Physical Simulation Experiment on the Quantitative Characterization of Grouting Stones for Drilling with Pre-stressed Concrete-pile-cased Pile

自主研发了1套随钻跟管桩桩侧注浆物理模型试验系统,定量表征了桩侧形成的注浆结石体。得到如下结论:浆液的厚度表现出下部厚上部薄、远离出浆口位置变薄靠近注浆口位置变厚的变化规律,这与浆液的黏滞性及浆液自重造成的压力损失密切相关;以出浆口所在轴线为对称轴,两侧浆液的厚度并不是严格的对称关系,右侧浆液的厚度大于左侧浆液的厚度,这与浆液和土体的非均质性有关;单孔静压注浆时,如果未设置排气孔,则在出浆口对面的一侧空气容易被浆液密封从而导致出浆口对面一侧注浆效果较差,这充分说明了随钻跟管桩桩侧布置出气管的重要性;随着距离出浆口的水平距离越来越远,浆液的厚度也越来越小,且高程越大浆液厚度下降的速度越大;如果模型桩的直径足够大,1个注浆口就很难满足注浆的要求。

A physical model test system for the grouting of the drilling with pre-stressed concrete pile cased pile(DPC pile)was independently developed,based on which the grouting stones formed on the side of this kind of pile was quantitatively characterized and the conclusions were obtained as follows.The thickness of the grouting stone shows a law"thick at the bottom and thin at the top"and"the thinner the position away from the outlet,and the thicker the position closer to the grouting port",which are closely related to the viscosity of the slurry and the pressure loss caused by the weight of the slurry.Taking the axis of the grouting port as the symmetry axis,the thickness of the slurry on both sides is not strictly symmetrical.The thickness of the right slurry is greater than the thickness of the left slurry,which is related to the heterogeneity of the slurry and the soil.During single-hole static pressure grouting,if no vent hole is provided,the air on the opposite side of the slurry outlet is easily sealed by the slurry,resulting in a poor grouting effect on the opposite side of the slurry outlet,which fully illustrates the importance of arranging the gas outlet pipe on the side of DPC pile.In the lateral direction,as the horizontal distance from the slurry outlet becomes farther,the thickness of the slurry becomes smaller.The greater the height,the greater the speed at which the slurry thickness decreases.If the diameter of the model pile is large enough,a grouting port is difficult to meet the requirements of grouting.