灌注桩套管振动贯入过程模型试验及数值模拟

发布时间：2019-03-13 17:40

【摘要】：为了研究灌注桩套管振动贯入引起的施工效应,通过物理模型试验,对套管贯入过程及贯入过程中孔隙水压力、水平向挤土应力和土塞闭塞程度的变化规律进行了分析;建立了能够有效模拟灌注桩套管振动贯入过程的数值分析模型,并对物理模型试验进行大变形数值模拟及对比.研究结果表明:灌注桩套管贯入深度每增加0.2 m,超孔隙水压力和水平向挤土应力分别增加1 k Pa和8 k Pa,但挤土效应的影响范围主要集中在距离套管中心半径为6倍管径的范围内;由于套管壁与土体的反复剪切,产生不完全闭塞的土塞,套管端部形成环形土拱,此段土塞承担了80%的内摩阻力;随着套管直径增大,土塞闭塞程度由不完全闭塞过渡到完全非闭塞状态;套管贯入相同深度时,饱和砂土地基中土塞高度为干砂地基中土塞高度的1.2倍.
[Abstract]:In order to study the construction effect caused by vibration penetration of cast-in-place pile casing, the variation regularity of pore water pressure, horizontal soil extrusion stress and blocking degree of soil plug in the process of casing penetration and its penetration were analyzed by physical model test. The numerical analysis model which can effectively simulate the vibration penetration process of cast-in-place pile casing is established, and the large deformation numerical simulation and comparison of the physical model test are carried out. The results show that when the penetration depth of cast-in-place pile casing is increased by 0.2 m, the excess pore water pressure and horizontal soil extrusion stress are increased by 1 k Pa and 8 k Pa, respectively. However, the influence range of soil squeezing effect is mainly concentrated in the range of 6 times the diameter of pipe from the center radius of casing. Because of the repeated shear between the casing wall and the soil, the soil plug is not completely blocked, and the annular soil arch is formed at the end of the casing, which bears 80% internal friction resistance. With the increase of casing diameter, the clogging degree of soil plug changes from incomplete block to complete non-blocking state, and when the casing penetrates into the same depth, the height of soil plug in saturated sand foundation is 1.2 times that of soil plug height in dry sand foundation.
【作者单位】：福州大学土木工程学院;
【基金】：国家自然科学基金资助项目(41272299)
【分类号】：TU753.3

【相似文献】