.第二章浅基础........................................................................22.1地基承载力计算...............................................................22.2基础底面尺寸.................................................................42.3基础沉降.....................................................................62.4软弱下卧层...................................................................62.5地基稳定性计算..............................................................112.6无筋扩展基础................................................................112.7扩展基础设计................................................................14第三章连续基础....................................................................173.1条形基础与交叉梁基础........................................................173.2倒楼盖与静定分析法..........................................................18第四章桩基础......................................................................194.1桩的竖向承载力与抗拔承载力..................................................194.2桩的沉降....................................................................234.3桩的负摩擦..................................................................274.4桩的水平承载力..............................................................284.5桩承台的设计................................................................29第五章地基处理....................................................................335.2排水固结....................................................................335.3刚性桩复合地基..............................................................34第七章挡土墙......................................................................387.1土压力计算..................................................................387.2挡土墙设计原理..............................................................39..基础工程课程习题第二章浅基础2.1地基承载力计算....基础底面尺寸2.2值力的内基础顶面载荷效应标准组合传至独7-2【例】某柱下矩形单基础。已知按值特征承载力=18.5KN/m3,其重度为γ地基粘Fk=920kN,Vk=15KN,MK=235KN.m；地基为粉质土，d=1.2m，试确定基础地面尺寸。ηd=1.6)基础埋深fak=180kPa(ηb=0.3,）求修正后的地基承载力特征值【解】（1?则假定基础宽度b<3m,?????200.72kPa18.5??1.2-0.5??d?0.51.6=180????ffmakad2）初步按轴心受压基础估算基底面积（F9202K5.2mA???01.2200.72-20?df??Ga。取基底长短边之比A=5.2×1.2=6.24m2，则考虑偏心荷载的影响，将底面积A0增大20%A1.77m?b?。l/b=2，得取，b=1.8m,l=3.6m2..3）验算地基承载力（基础及其台阶上土重155.52kN?1.8?1.23.6?Ad?20??G?GK基底处力矩m248.5kN?0.9?M?235?15K偏心矩Ml248.5K0.6m?0.23???e?6155.52920?F?GKK基底边缘最大压力G?F0.236?6e920?155.52????KK240.86kPa1.2f??229kPa?11p????????amaxk3.61.8?Al3.6????合适。满足要求，故基底尺寸长l=3.6m,b=1.8md=1.5m,基础埋墙下条形基础在荷载效应标准值组合时，作用在基础顶面上的轴向力Fk=280kN/m,【例】地基承载力特征值kN/m3,fak=150kPa，其重度γ＝１８b=0.3,室内外高差0.6m，地基为黏土（ηηd=1.6)求该条形基础宽度。1）求修正后的地基承载力特征值【解】（d>0.5m，故进行性地基承载力深度修正。假定基础宽度b<3m,因埋深????178.8kPa??1.5-0.518??F?f??d0.5150??1.5?mdaak）求基础宽度（20.6m，故基础自重计算高度因为室内外高差0.61.8m1.5+??d2基础宽度：..F280K?b??1.96mf??d178.8-20?1.8Ga取b=2m，由于与假定相符，最后取b=2m2.3基础沉降2.4软弱下卧层【例7-3】有一轴心受压基础，上部结构传来轴向力FK=850kN,地质条件如图所示，试根据...