建筑桩基础技术规范.doc

目录
第1 章概论..
1. 1 桩基技术标准演进与桩基技术发展…..
1.1. 1 桩基技术初始发展阶段
一一-制订《工业与民用建筑灌注桩基础设计与施工规程)) JGJ 4-80 ... ... ... ...... ... ... 1
1.1. 2 桩基技术加速发展阶段
制订《建筑桩基技术规范)) JGJ 94 -94 ........…·
1. 1. 3 桩基技术全面进步阶段
一一修订《建筑桩基技术规范)) JGJ 94-94 ，出台JGJ 94-2008 ............ ............ 2
1. 2 规范修订概要........……·…..........................…..........…..................…................ 4
1. 2. 1 调整的主要内容..............…...............................................................……. 4
1. 2. 2 增加的主要内容…………........…........ ......................"....…....................................…. 5
第2 章桩基设计基本规定.................………………………………………………………………. 6
2.1 建筑桩基设计等级划分………………………………………………………………………… 6
2. 1. 1 划分建筑桩基设计等级的目的和原则.... .. ...... ...... ...... ...... .... .. ...... .... ~ ...... ...... ...... ...... ...... ...." ...... ...... .. " .. ...... ..….. 6
2. 1. 2 建筑桩基设计等级具体划分….........................….......….........…...............…. 6
2.2 桩基的承载能力极限状态设计..............…........…................…............................ 7
2.2.1 桩基承载能力极限状态设计演变..........................…..............................……. 7
2.2.2 有关国家和地区规范关于桩基承载能力设计概况........….................................. 11
2.2.3 桩基结构承载能力极限状态设计….................................…..................……·… 13
2. 3 桩基的正常使用极限状态设计...-...........…..................…........................….......... 13
2.3.1 桩基正常使用极限状态内涵................…................…........…....................... 13
2.4 桩的类型与选型.......….........…................................….................................…. 18
2.4.1 桩的要素….."".................................................…..................…….......…… 18
2.4.2 桩的分类…........................................................…........................…....... 19
2.4.3 桩型选择.........…·…….................….........….............................................. 21
2.5 桩端持力层选择………………………………………………………………………………… 25
2.5.1 桩端土支承刑度对侧阻力的影响.................................................................. 25
2.5.2 端阻力的深度效应..........................…........….......….................................. 26
2.5.3 结合多种因素选择桩端持力层.......................……..................…................... 27
2. 6 承台形式和基桩布置.......................…...........................-......…·….......….......…. 33
2.6.1 承台形式设计....................................................................，...................... 33
2.6.2 基桩布置…….................…..................…....."............….....................'....... 35
2. 7 桩榄基础变刚度调平设计...............................................…............................... 36
2.7.1 传统设计理念的若干误区........….........………...............…......................……. 37
2.7.2 变刚度调平优化设计…........….................................…............................... 41
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目录
本章参考文献....... .….........…....................................…........ .…............. .... ....…. 59
第3 章桩基构造………………………………………………………………………..……….......… 61
3. 1 概述…….....….........….....................................................................….......... 61
3. 1. 1 考虑基桩的工作性状.......................…........…..........(1.....….........…….......... 61
3. 1. 2 特殊地质条件下的基桩……................................…........................….......... 61
3. 1. 3 桩基的耐久性................….......….....11'...……. ... ... ... . ~. .….........…....,..,........... 62
3. 1. 4 桩土、承台和上部结构的共同作用....................….........……......................... 62
3.2 基桩构造……...............….........…...............…..........................…"'.................… 62
3.2.1 灌注桩桩身构造.............. .…....... ................ .... ......................…............................ 62
3.2.2 扩底灌注桩....... ... ...............................................…................................ ..…. 64
3.2.3 混凝土预制桩…… ·H·H·-- ， ....................ui-- ………..........…………..........………. 65
3.2.4 预应力混凝土空心桩…..........……..........……..............…........................……. 65
3.2.5 钢桩的构造....................…..................…….........…........….......….........…. 67
3.3 承台构造........…. ... .... .... ... . ~. ,.... ... ... .….........,.......\.......\11..…..................….......…. 70
3.3.1 承台的最小宽度和厚度.................….......... ,....... .............. .... ..... ...............111......…70
3、3.2 配筋模式及最小配筋丰.............c......................................... ……........................ 70
3.3.3 承台混凝土耐久性.........……..........…........…………......….........…………....... 73
3.3.4 承台与桩、柱及连系梁之间的连接........… H·H·-·?H·H·-?-H·H·- …... ... .... ........……. 73
本章参考文献.................于……………...…................................................................. ..……….. 74
第4 章桩基竖向承载力......................................... .…...... .…..........................................…. 75
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4. 1 概述........…...........................................................................…................ 75
4. 1. 1 羊、群桩的承载变形特性…........….... .... ........ ................................................…. 75
4. 1. 2 一般建筑物基桩荷载效应计算…........…·…........…....................................…. 75
4. 1. 3 考虑承台(包括地下墙体)、基桩协同工作和土的弹性抗力作用
分析方法计算基桩荷载效应................. .…................................….................. 77
4.2 桩基竖向承载力确定与验算................... ..... ......................….........…...................... 77
4.2.1 桩基竖旬承载力计算.................…...............… .......c.. ……........……….......…. 77
4.2.2 复合桩基竖向承载力.......................…...........….........….........…................... 81
4.2.3 桩基竖向承载力验算........................………...............….........…..........，......... 85
4. 3 桩基竖向承载力的时间效应.....'........................................….....'.....…................... 87
4.3.1 饱和软土中摩擦型挤土桩承载力的时间效应..............，....…...................….......... 87
4.3.2 崭性土中钻孔桩承载力的时间效应….................................................................……. 91
4.3.3 考虑时间效应基桩承载力验算................. ..... ....... .'......................….........…·…… 91
4.4 特殊桩型的单桩竖向极限承载力................'..........…......~.，...................，.............O'O.. 92
4.4.1 大直径灌注桩的竖向承载力.......... .,........,................. ........ ...................…................... 92
4.4.2 铜管桩的竖向承载力......... '.,.' .....….........…... ..........……........…........………........ 95
4.4.3 预应力混凝土空心桩的竖向承载力………........…......................................……. 98
4.4.4 嵌岩桂的竖向承载力….. ........ ... ..... ... ... ..... .,.. .......…..................... ....,...………..… 99
4.4.5 后注浆灌注桩的竖向承载力........................…..........…..................….......... 102
4.5 特殊条件下桩基的竖向承载力..................................…..................................... 107
目录
4.5.1 软弱下卧层验算........…..........……….........…....................................……. 107
4.5.2 桩基负摩阻力........…..................…….........….................... 111............................................……. 109
4.6 桩基抗拔承载力..............….........…..........…..................…...... ...... ... ... ......... 115
4.6.1 概述….................................……….........….........….........…................... 115
4.6.2 等截面桩........….................................................................................. 116
4. 6. 3 扩底灌注桩............................................…........................................... 120
4.6.4 后张预应力灌注桩…...............………........………..................................... 121
4.6.5 抗拔桩的群桩效应及其承载力.........................................…..................…. 124
4. 6. 6 抗拔桩选型..............…·气........................................................…….......... 125
4. 7 建筑桩基整体稳定性验算..........………………………………………………………….. 128
4.7.1 平地建筑桩基的整体稳定性问题................................….........…................ ..……. 128
4.7.2 坡地、岸边建筑桩基的整体稳定性验算……...........…...............…................ 128
本章参考文献..................…........................ .…....................... .……........ .…........ .…. 128
第5 章桩基水平承载力和位移….................….......................................................... 129
5.1 概述........……………………………………………………………………………………. 129
5.2 单桩水平承载力….................….........…......................................................... 130
5.2.1 羊桩水平静载试验….................................….........……............. ...............…. 130
5.2.2 水平荷载下单桩的计算...........................................................….........…. 133
5.2.3 单桩水平承载力特征值.............................…·…….............................……. 135
5.3 水平荷载下群桩基础的计算............................................…...........................…. 137
5.3.1 群桩基础水平承载力简化计算.......................................................... .............…. 137
5.3.2 考虑承台(含地下室侧墙)一桩一土共同作用的分析计算........................…… 140
本章参考文献... ...111.. 111... 111 111..…..........…………………………………………………………… 164
第6 章桩基沉降计算...，......…................………..……………………………………………… 165
6. 1 概述….......................…....... .….........................................…·….................. 165
6. 1. 1 建筑桩基沉降计算的工程意义........…........…................…..................……. 165
6. 1. 2 既有沉降计算方法简述..................….........…............................ .….........…. 165
6.2 单桩、单排桩、疏桩基础的沉降计算....... .…..................…...........................…. 174
6.2.1 对Geddes 应力计算的改进考虑桩径影响的Mindlin 应力系数.......…........... 174
6.2.2 考虑桩径影响的Mindlin 解计算单桩、单排桩、疏桩基础沉降一一规范法......... 216
6.3 中小桩距群桩基础沉降计算..............................…......................................…. 222
6.3.1 中小桩距群桩基础沉降变形特征…............................................................ 222
6.3.2 等代墩基法的改进….............................................................................. 225
6..3.3 等效作用分层总和法一一一规范法........….........….........................…….......... 227
6.3.4 弹性理论法计算桩基沉降的改进.........……..... .....…...... ................. ... ......…....... 230
6.4 软土中减沉复合疏桩基础的设计和沉降计算.........…........…............................... 236
6..4.1 概述................................... .…….........…….........….........…………................ 236
6.4.2 软土中减沉复合疏桩基础的承载变形特性.........~........................................... 236
6.4.3 复合桩基承载力计算←→一承台面积和桩数确定........................................….. 237
6.4.4 复合疏桩基础沉降计算...... ....…................................................................. 238
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自录
6.4.5 减沉复合疏桩基础桩身受压承载力计算.........…........................................... 240
6.4.6 减沉复合疏桩基础设计案例….................................................. ..…·…........….........….......... 240
本章参考文献……............ .................. ............. .... 11.:............................................. .......................……......................... 242
第7 章桩基结构承载力计算........…………………………………………………………………. 244
7. 1 桩身承载力…............…………………………………………………………41..............…. 244
7. 1. 1 钢筋混凝土轴心受压桩正截面受压承载力..............… ..............u.................. 244
7. 1. 2 偏心受压桩.......................….........….................................................... 247
7. 1. 3 轴心受拉桩.................………..........…..........……·…................................. 247
7. 1. 4 预制桩桩身承载力….................…...........................................….......….. 250
7.2 承台承载力...............…...........................…........…..........................…......... 252
7.2.1 四桩及以上柱下独立桩基承台… ·H·H·-··..Lunu--H·H·-··H·H·-··H·H·-H·H·-··H·H·-253
7.2.2 柱下放立三桩承台..............….........…..................….........…................... 265
7. 2. 3 柱下放立两桩承台................................................ 111.................................... 111................................................................…. 271
7.2.4 或形承台…........…...................................................…......................…. 276
7.2.5 砌体墙下条形承台梁..............................u.............................................. 278
本章参考文献.... .......…................................ a...................... …............................................................... .……. 280
第8 章桩基础抗震…………………………………………………………………………………… 281
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8. 1 桩基震害……………………………………………………………………………………… 281
8. 1. 1 非液化土中桩基的震害…............................. ............................. .......................…. 281
8. 1. 2 液化土中桩基的震害........……….........................….................................. 286
8.2 桩基抗震设计的基本要求..................…………………………………………………… 291
8.2.1 一般规定.............................…............…….........……………................... 291
8.3 桩基竖向抗震承载力验算……..................….................................................... 294
8.3.1 可不进行抗震承载力验算的桩基…....................................................... ..…....... 294
8.3.2 非液化土中低承台桩基的竖向抗震承载力验算….................…...............……. 294
8.3.3 液化土中桩基的竖向抗震承载力验算....................….........…..................…. 295
8.4 桩基水平抗震承载力验算………………………………………...………………………… 296
8.4.1 非液化土中低承台桩基水平抗震承载力验算…... ."........................................... ..…. 296
8.4.2 液化土中桩基水平抗震承载力验算…................. ..…..................................... 298
8.5 坡地岸边桩基整体稳定性抗震验算......，...........….........….........….........….......... 299
8~ 5. 1 影响坡地岸边建筑桩基整体稳定性的因素…….............................................. 299
8.5.2 土质边坡桩基整体稳定性验算一一圆弧滑动条分法........".......... ..................... ...… 299
8.5.3 存在外倾基岩或软弱层折线形滑动面桩基的整体稳定性验算
一-折线形滑动面传递系数法………………………………………………………… 304
8.6 桩基结构承载力抗震验算...................... .'... .'....................….........……................ 310
8.6.1 钢筋混凝土构件的承载力抗震调整系数YRE .................…............................ 310
8.6.2 承台结椅承载力抗震验算…........................................…......................…. 310
8.6.3 桩身结构承载力抗震验算.......................................................... .……........…........ 310
8.6.4 液化土中桩基础设计计算案例.......... .…..........…........…..................….......... 320
8.7 桩基抗震构造措施.. .'...... ........……………………………………………………………… 329
目录
8.7.1 桩身配筋.................….........".........................................................................…· 329
8.7.2 承台体系抗震构造措施……......................，........………..........................….......... 329
本章参考文献....................................... 111.. l1li...................."…..............................'....…............ ...... ...... .......... ...........……… 335
第9 章桩基施工..............….. .... ".. .,. ...... 111.... ...... . l1li.. 111 .... ...... ...... ...... ... ... .. .. .... .. ".... ....... ....... .. .. .. .... III! ....... ....... ...... .. .. t ~.哩....... ~........ 336
9. 1 概述….......，...................................….............................................….............. 336
9. 2 灌注桩施工….............................…............................................................. 336
9.2.1 灌注桩施工的共性问题.................................".............….......….........……. 337
9.2.2 泥呆在灌注桩施工中的应用........….........….........…........….......….........…. 339
9.2.3 泥菜护壁钻、冲孔灌注桩....................................…·…...........................….. 342
9.2.4 旋挖钻机成孔灌注桩…........…...................….........……..........……·…......... 345
9.2.5 沉管灌注桩和内务管灌注桩………………………………………………............... 346
9.2.6 干作业成孔灌注桩………...........................…............…..........………….......... 349
9.2.7 长螺旋钻