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目的:静钻根植竹节桩是一种由预制桩和水泥土组成的组合桩基,其桩身具有预制桩-水泥土和水泥土-桩周土体两个接触面。本文以桩土接触面剪切试验、模型试验和现场试验数据为基础,提出一种静钻根植竹节桩简化沉降计算方法,为静钻根植竹节桩的沉降计算提供依据;并通过所提出的简化计算方法对静钻根植竹节桩桩端水泥土扩大头以及桩周水泥土直径对静钻根植竹节桩承载性能的影响进行研究。创新点:1.通过剪切试验对预制桩-水泥土接触面的剪切性能进行研究,得到接触面侧摩阻力与相对位移的关系;2.建立同时考虑预制桩-水泥土接触面和水泥土-桩周土体接触面作用的静钻根植竹节桩简化沉降计算方法。方法:1.通过桩土接触面剪切试验,得到预制桩-水泥土接触面摩擦模型;2.通过对模型试验结果的分析,得到水泥土-桩周土体接触面摩擦模型;3.根据试验结果编写静钻根植竹节桩沉降计算程序,通过与试验结果的比较验证所提计算方法的可靠性;4.通过提出的静钻根植竹节桩简化计算方法对静钻根植竹节桩承载力影响因素进行分析与研究。结论:1.预制桩-水泥土接触面摩擦性能远优于水泥土-桩周土体接触面摩擦性能;2.由于水泥浆的渗透作用,水泥土-桩周土体接触面的初始剪切刚度有所提高;3.所提出的计算方法能够有效地计算出静钻根植竹节桩单桩在成层土体中的荷载位移关系曲线;4.桩端水泥土扩大头能够有效地提高静钻根植竹节桩桩端承载性能,并且增加桩周水泥土直径能够提高静钻根植竹节桩承载性能。
OBJECTIVE: Static drilled rooted bamboo pile is a composite pile foundation composed of prefabricated piles and cement soil. The pile body has two contact surfaces: precast pile-cement soil, cement soil and soil around the pile. Based on the shear test, model test and field test data of pile-soil contact surface, this paper proposes a simplified settlement calculation method for static drill rooted bamboo piles, which provides a basis for settlement calculation of static drill rooted bamboo piles, and proposes The simplified calculation method was used to study the influence of the diameter of the soil-enlarged head and the diameter of the cement-soil around the static drilled rooted bamboo pile on the bearing performance of the static drilled rooted bamboo pile. Innovation points: 1. The shear performance of the prefabricated pile-cement interface was studied by shear test, and the relationship between the frictional resistance at the contact surface and the relative displacement was obtained; 2. The precast pile-cemented soil contact surface and cement were established simultaneously. A simplified method for settlement calculation of static drill rooted bamboo piles with soil-soil contact surface. Methods: 1. Through the pile-soil contact surface shear test, the friction model of the prefabricated pile-cemented soil contact surface was obtained; 2. Through the analysis of the model test results, the contact surface friction model of cement soil-pile soil was obtained; The test results are used to compile the calculation procedure for the settlement of static drilled rooted bamboo piles. The reliability of the proposed calculation method is verified by comparison with the test results. 4. The simplified calculation method for the static drill rooted bamboo piles is proposed for the bearing of static drilled rooted bamboo piles. Force influence factors are analyzed and studied. Conclusions: 1. The friction performance of the contact surface of prefabricated pile-cemented soil is much better than that of cemented soil-clay contact surface; 2. The initial shear of soil-cement contact surface between cement and soil is due to the penetration of cement slurry. The rigidity has been improved; 3. The proposed calculation method can effectively calculate the load-displacement curve of the single pile of static drilled rooted bamboo pile in the layered soil; 4. The cemented soil expansion head at the pile end can effectively improve the static Drilling root-bearing pile bearing performance of bamboo piles, and increasing the diameter of cement soil around the pile can improve the bearing performance of static drill rooted bamboo piles.