【作者】 刘建峰；

【导师】 严驰；

【作者基本信息】 天津大学 ， 岩土工程， 2008， 硕士

【摘要】 桩基础是一种重要的基础形式,在铁路、公路、桥梁、港口码头、高层建筑等工程中应用十分广泛。而桩土界面摩擦特性对地基和上部结构物的强度及变形特性有着十分重要的影响,如何确定桩土之间的界面摩擦特性是桩基设计的关键问题,是研究桩侧摩阻力、进而分析桩基承载力和沉降的重要力学问题。虽然国内外学者在桩土界面摩擦特性的研究方面已经做了相当多的工作,但是目前的研究只集中在对粘性土和砂土的研究上面,对粉土的研究很少,面对像胜利油田埕岛粉土地基这样的实际工程时,几乎没有规范可查,这就为实际工程的设计、施工、检测和安全性等带来诸多不利的影响。本文就是在此情况下,为了填补国内外对桩与粉土相互作用特性研究的不足和空白,选用室内模拟试验,着重对钢桩与粉土的界面摩擦特性进行初步的试验研究。从试验的类型上分,桩土界面摩擦特性模拟试验可以分为直剪试验和拉拔试验两种。就试验方法的优劣而言,直剪试验与拉拔试验并没有太大区别,但是经过试验分析发现,与拉拔试验箱相比,直剪试验箱在研制方面还存在一些不足,所以从某种意义上说,研究桩土界面摩擦特性采用拉拔试验更具有实际意义。于是在对拉拔试验箱改进的基础上,本文选用拉拔试验的研究方法,通过研究钢板与粉土的界面摩擦特性,模拟出钢桩与粉土的界面摩擦特性。桩土相互作用的机理较为复杂,它既与土体的工程特性有关,也与桩体的特性有关。试验结果表明,含水量、拉拔速度和垂直压力对桩土界面摩擦特性均有影响,其中拉拔速度的影响不大,含水量和垂直压力的影响却十分显著。根据静止土压力原理,本文推导出桩侧极限摩阻力沿桩体深度的分布曲线,为进一步研究桩基的承载力和沉降做出重要的工作。更多还原

【Abstract】 The pile is an important foundation form, and it is extensively used in railways,roads, bridges, ports and high-rise buildings. Interface friction between pile and soilhas much influence on the strength and distortion of the ground base and the upperstructure, so it is a key concern in pile foundation design, and it is an importantmechanics to study the side friction which determined the holding capacity andsettlement of the pile foundation. Although many researchers have done a lot of work,most of which focus on clay and sand, researches about silt are much less. Facing theproject like CHENGDAO silt ground base of SHENGLI oil field, there is almost nocriterions to be base on, and which leads many deficiencies to designs, constructions,detections and safeties of the project. Under these conditions, aiming to fill up thedeficiency and blank of the interaction between pile and silt, a serious of model testsare carried out.The model tests of interface friction between pile and soil can be divided intodirect shear tests and pullout tests. They are not of big difference between the testmethods, but according to the analysis of the test instruments, the box of direct sheartest exist some deficiencies by being compared to the box of pullout test. So it isbetter to choose the pullout test for studying the interface friction between pile andsoil in a sense. Based on the improved box of the pullout test, this article employs thepullout method to study the interface friction between steel plate and soil, whichinduce the interface friction between steel pile and soil.The mechanics of interface friction between pile and soil is very complex, as itis not only related to the engineering properties of soil, but also it is related to theengineering properties of the pile. The moisture content, drawing speed and verticalpresser have some influences on the interface friction between pile and soilaccording to test results, and the drawing speed has only small influences while themoisture content and vertical pressure have significant influence. Based on themechanics of static soil, the distribution cure of the ultimate side friction resistancealong the pile depth is deduced, which is useful for the study of holding capacity andsettlement of pile foundations.更多还原