The installed parts of the foundation system may be footing, mat foundation, slab foundations, and caissons or piles, all of which are used to transfer load from a superstructure into the earth. These parts, which transmit load from the superstructure to the earth, are called the substructure.
荷载(load)上部结构(superstructure下部结构(substructure)基础(foundation, footing)地基(subgrade, foundation soils)
3.1 工程地质勘查(engineering geological investigation)
一、勘察(investigation)与测绘(contouring )的目的 :地貌和地质条件(geological condition )2、(选址
勘察)(site selection )。初步勘察(preliminary investigation )。详细勘察(detail investigation)。
1、刚性基础(rigid foundation)砖、石、素混凝土(plain concrete) 2、扩展基础(spread foundation)
Spread foundations are used to spread the loads from columns or walls to the underlying soil or rock. When each footing supports only one column, it is square. Footings supporting two columns are called combined footings and may be either rectangular or trapezoidal. Footings supporting walls are continuous footings. Mat or raft foundation are large, thick, and usually heavily reinforced concrete mats which transfer loads from a number of columns or columns and walls to the underlying soil or rock. Mats are also combined footings, but are much larger than a footing supporting two columns. The sizes of footings are determined by dividing the loads to be imposed at the base of the footings by the allowable bearing pressure which can be imposed on the soil or rock of the earth. 钢筋混凝土(reinforced concrete)
按构造分类:1、单独基础(isolated foundation)柱(post) 2、条形基础(continuous footing)墙(wall) 3、筏板基础(mat foundation)地基承载力(bearing capacity of foundation soil ) 4、箱形基础(box foundation)5、壳体基础(shell foundation)3.3 深基础(deep foundation)类型: 1、桩基础(pile foundation)的分类:(1)按桩身材料分类:木桩(timber pile)、混凝土桩(concrete pile)、钢筋混凝土桩(reinforced concrete pile)、钢桩(steel pile)、其它组合材料桩(composite pile)。(2)按施工方法分类:按施工方法可分为预制桩(prestressed pile)、灌注桩(cast–in-place pile )两大类。(3)按承载性状分类:端承型桩(end-bearing pile )和摩擦型桩(friction pile )。2、地下连续墙(continuous concrete wall, slurry-wall )3、墩基础(pier foundation )在人工或机械成孔的大直径孔中浇筑混凝土(钢筋混凝土)而成,我国多用人工开挖,亦称大直径人工挖孔桩。4、沉井基础(open-end caisson foundation )5、沉箱基础(caisson foundation)
3.4 不均匀沉降问题(differential settlement problem)变形(deformation )差异沉降(unequal /differential settlement )额外应力(additional /superimposed stress)裂缝(chink ,breach, crack )沉降缝(settlement crack )砌体结构(block construction, masonry structure)圈梁(collar tie beam , bond beam ) 3.5 地基处理(foundation treatment) 一、地基处理方法
1、 换填法2、预压法3、强夯法4、振冲法5、深层搅拌法6、砂石桩法7、土或灰土挤密桩法
2、 .地基处理技术的发展 :1、土的“加筋法”(reinforcement method );2、土工合成材料、砂井预压和塑料
排水带; 3、“强夯法”(dynamic compaction )和“振动水冲法”等;4、真空预压法(vacuum preloading method);5、高压喷射注浆法(high-pressurized jet grouting)。
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