The mechanics property of rigid pile composite foundation in roadbed in these days , composite foundations have been extensively used . especially the rigid pile composite foundation is paid attention to in practice engineering . but less research work has been done , this paper works on it 复合地基目前在我国得到了广泛应用，特别是近期刚性桩复合地基在地基处理中应用较多，但对其的研究还较少，本文就依托一个用复合地基处理路基的工程，研究路基中的刚性桩复合地基的性状。
The two models of rigid and elastic piles have been discussed respectively , in which the anchor cable will be regarded as an elastic hinge . under the consideration of deformation harmony of anchor cable with piles bodies and pile bottom conditions , the solutions of the internal forces distribution along piles bodies are presented 本文分别按刚性桩和弹性桩两种物理模式，将锚索视为弹性绞支座，利用抗滑桩和锚索位移变形协调条件，计算出不同桩底条件下抗滑桩的内力分布。
The rule of settlement and pore stress is educed too . then it is compared with the case which is found in site . finally , the paper studies the computing method of pile to soil stress ratio of rigid pile composite foundation with cuhion , and these conditions are thought that the top of pile pierce into cushion and the bottom of pile pierce into underlayer . lt is assumed that the cushion is ideal elastic mass and ideal elastic - plastic mass , then the formula is developed and all parameters " effects to stress ratio of pile to soil are discussed 最后，推导出了带垫层的刚性桩复合地基桩土应力比的计算公式，这个公式将垫层分为弹性体和理想弹塑性体两种情况分别进行推导，考虑刚性桩刺入垫层和下卧层的情况，并对公式进行了分析，得出了在刚性桩复合地基中桩土应力比随着垫层模量和桩模量的增大而增大，但都有一极限值，随桩间土模量的增大而减小，也有一极限值。
Composite foundation with cfg piles developed from the later of 1980s " is a technique of composite foundation with rigid piles . it has been wildly used in large quantity of construction for its high ratio piles bearing capacity , notable improvement in bearing capacity of subsoil , adjustable , lower construction cost ( compared with pile foundation engineering ) and wildly application ( used in many kinds of regional soil such as soft soil > loess , expansive soil etc . and in multi - storey - , sub - high - rise buildings ) Cfg桩复合地基技术是20世纪80年代末发展起来的一种刚性桩复合地基技术，以其桩承担荷载比例高、地基承载力提高幅度大、可调性强、工程造价低廉(与桩基工程相比)和应用范围广泛(在软土、黄土、膨胀土等多种区域地基中应用，应用于多层、亚高层和高层建筑)而为大量工程所采用。
Therefore , the main problems are studied in this paper hereinafter : 1 . the designing thought of cement flyash gravel piles composite foundation is provided , which is based on how to raise the bearing capacity and how to reduce the deforming of composite foundation . the designing thought is analyzed , in which the problems are disputed at present whether cement flyash gravel piles are rigid piles and the conception of composition are studied in this paper 因此，本文所作的工作主要有： ( 1 ) cfg桩复合地基设计思想的提出是基于进一步提高复合地基承载力和减少变形这一思路，本文对这一设计思想进行了分析，并探讨了其中目前存在争议的cfg桩是否为刚性桩和复合概念的问题。
Secondly , by using the great fem programme , analyzes the mechanism of bearing and deformation of rigid - soften composite piles foundation . draw a conclusion : exist a specific value , when the number of the rigid pile less than it , increase the number of the rigid pile , effect of reducing the settlement of rigid - soften composite piles foundation is distinct , on the contrary , when the number of the rigid pile more than it , increase the number of the rigid pile , effect of reducing the settlement of rigid - soften composite piles foundation is indistinct . finally , analyze and sum up some important design ' s constitutes of the rigid - soften composite piles foundation 其次，采用有限元计算程序，对刚柔复合桩基进行了三维有限元分析，考察了在不同荷载水平下，不同刚柔性桩比例的情况下，复合地基的平均沉降量、土体的沉降等值线和应力等值线以及刚性桩和柔性桩桩顶荷载比值随不同基础荷载水平的变化规律，得出了一些具有实际指导意义的结论：当总桩数不变，长桩比例增加到一定程度时，再增加刚性长桩的数量对地基整体沉降几乎没有什么效果；刚柔桩分布一定，柔性桩实际承载力小于其极限承载力时，外加荷载的增加，刚性单桩和柔性单桩所承当荷载的比值基本不变。
