1.It analyses the main affection reasons of quality of pile itself of drilling cast-in-place pile and the part strength of core pile,and represents the control steps of pile foundation quality in detail from the assurance steps of the concrete strength of the upper pile and the pile foundation quality and the technology points of concrete cast-in-place construction,to give a reference to the construction people of pile foundation.
分析了影响钻孔灌注桩桩身质量及孔桩上部分强度的主要原因,从桩上段混凝土强度的保证措施、桩基质量的保证措施、混凝土灌注施工的技术要点三方面详细阐述了桩基质量的控制措施,以供桩基施工人员参考。
2.Concrete-cored DCM (Deep Cement Mixing) pile is a new kind of composite pile that is developed for the ground treatment in soft clay ground. The composite pile is composed of an external DCM pile socket and an inner precast concrete pile that is inserted right after the completion of the DCM pile.
砼芯水泥土搅拌桩是一种适用于软土地基处理的新桩型,它是在水泥土搅拌桩中即时插入高强度的预制混凝土桩形成的复合桩。
3.In the light of vertical static load test in situ of tension pile in permanently frozen ground at Qingshuihe of Qing-Zang Railway,the paper makes thorough study of freezing strength of frozen soil around pile and limit bearing capacity for vertical tension of foundation pile,analyzes and compares the results of load test for foundations of direct hole pile and pedestal pile,which have provided scientific basic for pile foundation of Qingzang Railway.
结合青藏铁路清水河多年冻土地区抗拔基桩的竖向静载现场试验,对桩周冻土冻结强度、基桩竖向抗拔极限承载力等进行了深入的研究,并将直孔桩、扩底桩两种不同桩基础的荷载试验结果进行了分析比较,为青藏铁路桩基础设计提供了科学依据。
4.In order to reveal load mechanism and failure mode of thick pile caps, by means of the test of 1/4scale models of thick pile caps with six piles and posthandling study of 3dimensional nonlinear finite element ADINA, this paper points out the shortage, which is that the design of pile caps is carried out by flexural strength in Chinese technical code for building pile foundations JGJ9494 and American reinforcement concrete building construction code ACI31802, promulgates that the failure mode of thick pile caps is punching failure and load transfer mechanism is the strutandtie, which is that zones of concrete with primarily unidirectional compressive stresses are modeled by compress struts, while tension ties are used to model longitudinal reinforcement over pile.
摘要为揭示厚承台的传力机理和破坏形式，通过对4个1:5比例的六桩厚承台的模型试验研究与三维非线性有限元ADINA的后处理研究，指出中国建筑桩基技术规范JGJ9494与美国钢筋砼房屋建筑规范ACI31802规范中，承台以弯曲强度进行配筋计算的设计方法之不足，揭示出厚承台的破坏模式是冲切破坏，传力机理是以带有主要单向压应力的砼区域作斜压杆，桩顶区域的纵筋作拉杆的空间桁架。
5.Influencing regularities with regard to soil arching effect, the ratio of the load on pile, the stress-reduction ratio and the ratio of stress between pile and soil are found by parametric analysis. The influencing factors include center-to-center spacing between piles, pile length, pile diameter, pile cap diameter, embankment height, pile modulus, soil modulus, etc.
通过考察桩间距、桩长、桩帽置换率、桩径、填土高度、桩侧土模量、桩体模量、路堤填土模量等参数的变化，揭示了其对桩体荷载分担比、应力降低比、土拱效应、平均桩土应力比等的影响规律，得到了一些有益的结论。
6.During the low strain dynamic test of the foundation pile, the adoption of the velocity sensor to the direct measurement of the relative displacement of the pile head is helpful to reducing the improper dependence upon the measured intrinsic frequency valuesof the pile soil system in calculating vertical bearing capacity of the single pile, and is hence conducive to raising the accuracy of the calculated vertical bearing capacity of the single pile.
基桩低应变动测中，采用速度传感器直接测出桩头的相对位移，在推算单桩竖向承载力时，有助于降低对桩土体系固有频率测定值的过分依赖，从而有利于提高单桩竖向承载力推算值的准确程度。
7.It is indicated that as for the manpower dig?hole pile installed in silt, clay and silty soil, residual soil and sandy clay, when pile?soil relative displacement reaches 3?7 mm, frictional force of pile side reaches ultimate state, and frictional force of pile side is 40%～50% of pile?top load or so.
研究结果表明:对于置于淤泥、粘土、粉土、砂质粘土、残积土的人工挖孔桩,当桩土相对位移达3～7mm时,桩侧摩阻力达到极限状态,此时,桩侧摩阻力约占桩顶荷载的40%～50%;
8.The bonding slip behavior between the prestressed concrete pipe pile and pile cap belongs to interfacial bond properties of new and old concrete,which is related to the strength of the concrete of pipe pile and pile cap,surface roughness of pipe pile,interfacial agent and the stress state.
预应力混凝土大管桩与桩帽混凝土之间的粘结性能属于新老混凝土的粘结问题,其粘结强度不仅与管桩和桩帽混凝土的强度大小有关,而且与管桩表面的粗糙度、界面剂的类型以及受力性质有关。
9.The effect factors of the distance of two piles, the length of pile, size of pile cap, modulus of cushion, modulus of underlying soil layers, modulus of soil besides pile cap and K_0 have been discussed for composite pile-soil stress ratio and the place of equal settlement section. 4. Based on reasonable assumption and elasticity theory, adopting the load transfer function method, the linear analysis of composite single pile with cap has been done.
4、基于合理假定和弹性理论,采用荷载传递函数法,对带帽复合单桩桩土相互作用的力学性状进行了线性分析,很到了复合桩体中桩体沉降、桩帽下土体的竖向位移、桩身轴向应力、桩帽下土体的竖向应力、桩身侧摩阻力与荷载水平、深度之间的控制微分方程,并得到其解析表达式。
10.Through analyse the test results of cast-in-place pile with the post grouting under different geologic conditions, Approach the influences on the bearing capacity of cast-in-place pile with grouting at pile end and pile side, List the prerequisites of the pile can be used under diffirent geologic conditions.
通过不同地质条件下采用后压浆工艺的钻孔灌注桩试桩结果的分析,探讨了钻孔灌注桩桩端压力灌浆及桩侧压力灌浆对提高承载力的影响,提出了不同地质条件下采用后压浆技术的条件。
