复合地基群井固结模型理论研究1)

A CONSOLIDATION MODEL OF GROUP WELLS ON COMPOSITE FOUNDATION1)

  • 摘要: 针对复合地基固结问题,考虑井阻和土体径竖向渗流的影响,建立 以"桩-土-桩"为单元的复合地基群井计算模型,采用解析解法,推导出瞬时载荷作用下复合地基群井固结解析解,讨论了复合地基固结特点和孔压等的变化规律。研究表明,复合地基群井固结模型为复合地基固结理论的研究提供了一种新思路,在井径比大于5 时,基于中心桩、边桩流量相等假设,复合地基群井固结理论所求固结度和传统固结理论所求固结度相差很小,可忽略不计;桩体渗透系数、内外扰动区土体径向渗透系数、土体竖向渗透系数越大,复合地基固结速率越快;堆载越大,最终达到稳定时的沉降量和竖向应变越大;地基表层土体的孔压消散速率和竖向应变速率大于地基深部土体。

     

    Abstract: For the consolidation problem on the composite foundation, with consideration of the influence of the well resistance and the vertical seepage in the soil radial direction, a calculation model of composite foundation group wells with pile-soil-pile as a unit is established. By using the analytical method, the analytical solution of the composite foundation group well consolidation under an instantaneous load is derived, as well as the consolidation characteristics and the pore pressure variation of the composite foundation. The study shows that the consolidation model of the composite foundation group wells provides a new idea for the theoretical study of the consolidation of the composite foundation. When the borehole diameter ratio is greater than 5, based on the assumption that the flow rates in the central pile and the side pile are equal, the difference between the consolidation degree calculated by the group well consolidation theory of the composite foundation and that calculated by the traditional consolidation theory is very small and negligible. The consolidation rate of the composite foundation increases with the increase of the pile permeability coefficient, the radial permeability coefficient of the soil in the disturbed zone and the vertical permeability coefficient of the soil. The larger the load is, the larger the settlement and the vertical strain will be. The pore pressure dissipation rate and the vertical strain rate of the surface soil are higher than those of the underneath soil.

     

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