本文選題：柱下獨立基礎(chǔ) + 梁板式筏形基礎(chǔ)��； 參考：《長安大學(xué)》2014年碩士論文

【摘要】：現(xiàn)行地基規(guī)范關(guān)于鋼筋混凝土淺基礎(chǔ)的沖切和剪切計算，存在一些不明確之處，本文主要針對GB50007-2002《建筑地基基礎(chǔ)設(shè)計規(guī)范》和GB50007-2011《建筑地基基礎(chǔ)設(shè)計規(guī)范》兩版規(guī)范中關(guān)于柱下獨立基礎(chǔ)沖切和剪切計算中存在的較大差異問題進行算例分析，并與歐美規(guī)范進行對比，得到影響柱下獨立基礎(chǔ)沖切和剪切計算的因素和各因素對沖切和剪切計算的影響規(guī)律，并提出相關(guān)建議；針對梁板式筏基底板沖切和剪切受力規(guī)律及其底板的單雙向板劃分問題，進行有限元模擬計算研究，得到梁板式筏基底板在均布荷載作用下，板格的變形和內(nèi)力分布規(guī)律及單雙向板的劃分界限。方便了工程設(shè)計，為地基規(guī)范的進一步完善提供了參考。 本文針對獨立基礎(chǔ)沖切、剪切破壞問題，，做了如下工作并得到相關(guān)結(jié)論： （1）對我國新舊《建筑地基基礎(chǔ)設(shè)計規(guī)范》中關(guān)于獨立柱下基礎(chǔ)沖切和剪切公式，進行算例分析，得到：當(dāng)基礎(chǔ)底面短邊尺寸小于或等于柱寬加兩倍基礎(chǔ)有效高度時，新規(guī)范的抗剪驗算算得基礎(chǔ)底板厚度要比舊規(guī)范按沖切算得的厚度大很多，新規(guī)范變化較大； （2）分析并得到了基礎(chǔ)底面寬度、長度和有效厚度對新舊規(guī)范擴展基礎(chǔ)沖剪驗算的影響規(guī)律。通過數(shù)據(jù)分析得知，底板長厚比可以很好的反應(yīng)舊規(guī)范沖切力和新規(guī)范剪切力之間的關(guān)系，當(dāng)長厚比大于4.0時，剪沖比值接近2.0，建議按新規(guī)范來進行驗算。當(dāng)長厚比小于4.0時，新舊規(guī)范計算差異較大，建議對新規(guī)范的抗剪驗算進行進一步的研究； （3）對中美歐三國規(guī)范中混凝土柱下獨立基礎(chǔ)抗剪驗算進行了大量的算例分析，找出影響受剪承載力和剪力效應(yīng)的因素。得到了基礎(chǔ)長度、寬度、有效厚度、配筋率、驗算截面位置對各國規(guī)范抗剪承載力和剪力效應(yīng)的影響規(guī)律，并對我國規(guī)范提出相應(yīng)建議。 本文針對梁板式筏基底板沖切、剪切受力規(guī)律及其單雙向板劃分問題做了如下工作： 通過ABAQUS有限元分析軟件對梁板式筏基進行建模，模擬實際狀態(tài)下梁板式筏基的內(nèi)力分布與變形，通過數(shù)據(jù)的分析討論，得到梁板式筏基板格內(nèi)力分布規(guī)律，提出梁板式筏基單雙向板的劃分建議。相關(guān)結(jié)論如下： （1）板格支承邊單元截面上的內(nèi)力在角部趨于0，隨著向跨中靠近內(nèi)力快速增大，在達到離板格角部1.6m處時，內(nèi)力趨于穩(wěn)定并達到峰值，內(nèi)力方向與截面有一個角度，在靠近跨中時接近45°； （2）通過大量數(shù)據(jù)的分析和討論，本文建議，選取長寬比ly/lx=3.0作為梁板式筏基底板單雙向板的劃分界限，明確了當(dāng)ly/lx3.0時應(yīng)全部按雙向板設(shè)計；當(dāng)ly/lx≥3.0時可按單向板設(shè)計，但應(yīng)在垂直于受力的方向布置構(gòu)造鋼筋，構(gòu)造筋的配筋率不宜小于長支承截面配筋率的15%。
[Abstract]:In the current foundation code, there are some ambiguities in the calculation of punching and shearing of shallow reinforced concrete foundations.In this paper, a numerical example is presented to analyze the large differences in the punching and shearing calculation of independent foundation under columns in GB50007-2002 Code for Design of Building Foundation and GB50007-2011 Code for Design of Foundation of Building Foundation.Compared with the European and American codes, the factors that affect the punching and shearing calculation of the independent foundation under the column and the law of the influence of each factor on the calculation of the punching and shearing under the column are obtained, and the relevant suggestions are put forward.In view of the punching and shearing force law of beam-slab raft foundation floor and its single and bidirectional slab partition problem, the finite element simulation calculation is carried out, and the results show that the beam-plate raft foundation floor plate is under uniform distribution load.The distribution law of deformation and internal force of plate lattice and the dividing limit of single and two-way plate.It is convenient for engineering design and provides a reference for the further improvement of foundation code.Aiming at the problems of punching and shearing failure of independent foundation, this paper has done the following work and obtained the relevant conclusions:1) by analyzing the formula of punching and shearing of foundation under independent columns in the new and old Code for Design of Building Foundation in China, it is obtained that when the size of short edge of foundation bottom is less than or equal to that of column width and twice the effective height of foundation,The thickness of the base plate calculated by the new code is much larger than that of the old code by punching, and the new code changes greatly.2) the influence of the width, length and effective thickness of the foundation bottom on the checking calculation of the expanded foundation of the new and old codes is analyzed and obtained.When the ratio of length to thickness is less than 4.0, the difference between the new code and the old code is great.3) A large number of examples are given to check the shear resistance of concrete columns under concrete columns in the codes of China, America and Europe, and the factors affecting the shear bearing capacity and shear effect are found out.The influence of the length, width, effective thickness, reinforcement ratio and section position of foundation on the shear capacity and shear effect of each country's code is obtained, and the corresponding suggestions are put forward for the code of our country.In this paper, the following work has been done on the punching and shearing law of beam-slab raft foundation floor and its single and bidirectional plate partition problem:The internal force distribution and deformation of beam-slab raft foundation are simulated by ABAQUS finite element analysis software, and the internal force distribution law of beam-slab raft foundation lattice is obtained by analyzing and discussing the data.The partition suggestion of single and bidirectional slab of beam-plate raft foundation is put forward.The conclusions are as follows:(1) the internal force on the section of the edge element of the plate lattice tends to be 0 at the angle, and increases rapidly with the internal force near the middle of the span. When reaching 1.6 m from the corner of the plate, the internal force tends to stabilize and reach the peak value, and the direction of the internal force has an angle with the section.Close to 45 擄near the middle span;However, the reinforcement should be arranged in the direction perpendicular to the force, and the reinforcement ratio of the structural reinforcement should not be less than that of the reinforcement ratio of the long bearing section.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU471.15

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