【作者】 司凤雄；

【导师】 栾茂田； 陈广志；

【作者基本信息】 大连理工大学 ， 水利工程/岩土工程， 2003， 硕士

【摘要】 土钉支护结构是当前比较常用的基坑支护形式之一。它既具有所有支护结构的共性，也有它自身的特性，本文综合了下面四方面内容来模拟土钉支护基坑，通过计算表明因为考虑了多种因素的影响，比较正确地分析了土钉支护机理。 其一，施工力学问题。在结构施工过程中，随着施工进程的变化，结构的形状也在不断的发生变化，与此同时作用在结构上的外载也随之而改变。基坑工程中重要是开挖荷载的计算，本文采用Mana来计算开挖荷载，Mana法是根据有限元法思想，将被挖掉的所有单元高斯点处的应力通过应变矩阵等效到节点上求得，该方法是比较有效的。 其二，主动支护形式。土钉支护法，以尽可能保持、显著提高、最大限度地利用基坑边壁土体固有力学强度，变土体荷载为支护结构体系的一部分。因此说土钉支护为为主动支护形式，这种支护方法具有传统支护形式所无法比拟的优点，值得在更大范围内推广使用。 其三，钉-土相互作用。由于土体与土钉的性质差异大，变形不一致，在二者的接触界面上常产生较大的剪应力，这种剪应力正是土体与土钉之间荷载传递的媒介，正确的研究分析接触面上的受力变形机理，剪切破坏的发展，荷载传递过程，并在计算中加以正确模拟是十分重要的。本文采用界面单元来模拟钉-土之间的相互作用，计算表明该单元能较好地模拟钉-土界面的作用实质。 其四，土钉支护边坡的稳定性验证。土钉支护的边坡需要验证其稳定性，本文采用当前比较流行的强度折减有限元进行了有土钉支护与无土钉支护边坡的稳定性分析，结果比较理想。更多还原

【Abstract】 The support structure of Soil nailing is one of the support form used in foundation pit. It not only has the common characteristics of foundation pit support form but also has some specialities. In this paper, four aspects of soil nailing were expatiated in detail. Many factors that influence the foundation pit support are considered, and the principle of soil nailing support is analyzed correctly.(1) Construction mechanics problem The structure shape will be changed along with the construction course. In the course of construction, the external loads will be changed accordingly. Foundation pit engineering is one of the unload problem in the construction mechanics. The computation of excavation load can be regard as the process that the stress of excavation surface is released completely and the excavation surface then changed into the free stress surface. The method of Mana is used to compute the excavation load in this paper. The method of Mana is one of the finite element method, and the method is rather effective.(2) Active support form The support form of soil nailing can preserve, enhance and impose the soil intension of foundation pit walls. It can change the soil loads into one part of the support construction system. So the soil nailing support can be regard as the initiative support form. The support form has the advantages and can be used widely.(3)Nailing-soil interaction It is well known that the characteristics of soil is different from the characteristics of soil nailing, and the distortion of them is disagreement. The shearing stress will come into being in the contact surface. The shearing stress is the medium that can transfer the load between soil and soil nailing. It is very important to analyze the principle of deformation, the development of shearing destruct, the process of load transfer and simulate them correctly. In this paper, the interface element is used to simulate the interaction between soil and soil nailing. It is indicated that the interface element can simulate the soil-nailing interface perfectly.(4) The validation of the slope stability by soil nailing The strength reduction finite element method is used to analyze the stability of the slope timbered by soil nailing and the slope timbered by the traditional support form. It is proved that the stability of the slope timbered by the soil nailing is ideal.更多还原