【摘要】 针对沿海地区深厚软土抛填石工程场地，既有建(构)筑物地基基础长期不均匀沉降严重的问题，在充分考虑周围场地条件，结合抛填石层、深厚软土层各自特征，满足加固处理要求的前提下，提出了一种上部为钢管桩下接高压旋喷桩支承于下覆岩层的组合桩型。通过理论分析、室内模型试验、现场静载试验、数值模拟计算以及工程实例，研究认为：1)高压旋喷钢管组合桩的竖向承载力主要由水泥旋喷桩体强度控制；2)随着注浆体厚度的增大，桩的沉降量随之减小，但随着注浆体厚度的持续增大，其缩减幅度也逐渐变小；3)粗糙度的影响存在一个阈值，其对承载力和位移的影响与土的工程性质有关；4)随着注浆体水灰比的增大，桩的承载力也随之增大。采用高压旋喷钢管组合桩对既有建筑下深厚软土抛填石场地进行加固处理具有一定的合理性和可行性。更多还原

【Abstract】 Aiming at the problem of long-term uneven settlement of foundations of existing buildings(structures) in deep soft soil rock-filled project sites in coastal areas, fully considering the surrounding site conditions, combining the characteristics of the rockfill layer and the deep soft soil layer, on the premise of meeting the requirements of reinforcement treatment, a composite pile type with a steel pipe pile under the high-pressure rotary jet pile supported on the overlying rock layer was proposed. Through theoretical analysis, indoor model tests, on-site static load tests, numerical simulation calculations and engineering examples, the study believes that: 1) The vertical bearing capacity of high-pressure rotary jet steel pipe composite pile is mainly controlled by the strength of cement rotary-sprayed piles; 2) As the thickness of the grouting increases, the settlement of the pile decreases, but as the thickness of the grouting continues to increase, the reduction of the pile gradually decreases; 3) There is a threshold for the influence of roughness, and its influence on the bearing capacity and displacement is related to the engineering properties of the soil; 4) As the water-cement ratio of the grouting liquid increases, the bearing capacity of the pile also increases. It is reasonable and feasible to use high-pressure rotary jet steel pipe composite pile to strengthen the deep soft soil rock-filled site under existing buildings.更多还原