建设工程—黄河大桩径超长灌注桩施工工法工艺.docx

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1、黄河河道中易塌孔地质大桩径超长灌注桩施工工法1、前言近年来，随着桥梁跨度的增大，大直径超长钻孔灌注桩在铁路、公路桥梁基础中得到广泛应用，相应的桩基直径和长度也在向大直径、超长方向发展。水上打桩也就成了一个难点，在泥浆制备上也就成了关键。传统的工艺是先制备泥浆，在置换泥浆,这样难以满足河床复杂地层。以海南州贵德县惠安黄河市政大桥建设项目为例，主桥设计存在以下特点:设计方面：桩径为2.0%桩长为60m,属于设计孔深为75m,属于大桩径，超深孔桩基施工；地质方面：地质复杂，存在大粒径飘石和易塌孔砂砾地层；地理位置：位于黄河上游，固有天下黄河贵德清的美誉，环保要求高；为了解决上述问题，在实践的基础上，

2、我们经过对整个施工过程的系统整理、归纳、分析，总结编制了本工法。7#、8#墩桩基具体位置如下图所示：图1-2地勘2、工法特点(1)适用性强根据本项目地理特征位置及设计情况，地质复杂，又是水上作业，采用常规桩基施工容易塌孔或者漏浆。本工法通过对桩基施工设备选型和调整常规的施工工艺，有效解决了复杂地质，大桩径，超深孔桩基施工困难。(2)安全性高本工法由于是先往护筒内回填黏土,冲击钻自主造浆，护壁效果较好，不容易引起漏浆；解决黄河水被污染的问题。(3)材料节省、经济性好本工法采取的工艺无需复杂材料以及特殊施工机具，桩基成孔质量有保障，一次性成孔灌注，能够有效的减少工期，利用黏土性能造浆，相对于先制备

3、泥浆等施工工艺都有明显的经济效益提升。3、适用范围本工法适用于复杂地层、易塌孔地质桩基施工。柩长较长的大柩。以及水中大直径桩基。4、工艺原理本工法是在常规的桩基施工基础上对灌注桩施工设备选型和利用黏土本身性能，通过工艺调整从而达到水上桩基施工目的。5、工艺流程及操作要点5.1工艺流程工艺流程见图5.IT5.2操作要点5.2.1整体结构要求黄河下游5.2.1-1桩基施工平面图LLJLLLLLLLLLLL1.卜-LllLLLLLULllllllliLLr层比：石件卵阴Llllllllli Llllllllli I-Lllllllli LlllllllliJLLLLLLLJXJL.tt Llllll

4、llll ULLLLLLLt ULLLLLLLh/ LllllllluvLlllllllli LLLLLLLLLi Ulllllllli Llllllllli UlllllllliLlllllllli Llllllllli Ulllllllli Llllllllli LlllllllliULLLUULLLi Ulllllllli Llllllllli UlllllllliJ Ulllllllli I-Llllullli,U卜 Llllllllli Ulllllllli5.2.1-2桩基施工剖面图工程需要先在钢栈桥上开孔，然后插打钢护筒，回填黏土，最后施工。5.2.2护筒设置本工程护筒埋深4m,

5、护筒内径大于桩径20公分，高出栈桥0.3m,护筒长16m。C-d护筒黄河Ulllllllll -LllLLLLLL LllllllllLL. LL. LL. LL. LL. ULL. _|二r -、LL层在-1 一IL石在tL -JL LLLUlllllllll Ulllllllll Llllllllll PrtIILtL-LLLLLLLLLLLIr _!_!_!-IL-J 八 LLLLLLLLy Llllllllli Ulllllllli Llllllllli-U-JLl _1_IL _1 J-ULl _! _U_I Llllllllli I-Lllllllli5.2.2-1护筒平面示意图5

6、.2.3施工方法及要点桩基平面如图所示:黄河上游黄河下游5.2.3T桩基平面示意图步骤1：先在栈桥上开孔，孔径比桩径大20cm,为护简孔。栈桥黄河JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL,；LLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLL

7、LLLLLLLLLLLLLLL而TELLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLHJ7TLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL*1zaLLLLLL.L.L-Lllllllllllllllllllllllllllllllllllllli-I-UL-I-L.I-I-LLLLLLl-L-LLLLLLLLLLLLLLLLLLLLLLLLjALLLLLLLLLLLLLLLLLLLLLLLLLLLLLL吐ILLLLIJJLLL口ALEZtLLLLLLLLLLLLLLLLLLLLLLLLLt5. 2.3

8、-2立面图步骤2：沿着护筒孔插打钢护筒，护筒埋深4m,外露0.3m,一节一节下护简，下一节护筒焊接一节，使护筒达到河床以下4m。-LlLLLLLL-LlLLLLLL-LlLLLLLL-LlLLLLLL-LlLLLLLL-LlLLLLLL1.LL-ULLLJ-11.L.LL.LL.LL.LL.LLL.LLL.J-JLJLJ.层并石匕：111.LIJJIULI1.lllllllliLlllllllliLlllllllli-J-JJ-ULLJ卜二tLL卜FLJ.JLLLLLLLLt-ULL-JL-IJ八.-LllLLLLUVLlllllllliLlllllllliLlllllllliLlllllll

9、liLlllllllli1.lllllllliLlllllllliLlllllllliLlllllllli5.2. 3-3护筒埋设步骤3：在护筒内回填黏土，填至距离顶部2.5,约40方黏土。一，HHUUUUHQn 口-JLL-J-I-ULXJ F-UJLL-UJ-J 口 LLLLLLLLJJ LLLLLLLL 世层建LL. LL. LLL. LLL. -U-T ,UL石井WulZw/Ll ,Ul 卜PHHBLlllllllli Llllllllli .U-J-U-J-J-JLl Lllllllllu Llllllllll OlllllllliLLLI LLLI LLrI-LLLULllllll

10、lli Llllllllli Llllllllli Llllllllli Llllllllli Llllllllli Llllllllli Llllllllli Llllllllli Llllllllli ,ULLLLLL-Jl Llllllllli .ULL-ULL 卜 Llllllllli Llllllllli Llllllllli Llllllllli5.2.3-4黏土回填步骤4：加水，使用冲击钻开打。泥浆池黄河-LLL-LLLLLLLLLLLLLLLLLLLLLLl-L.-LLLLLLLLLLLLLLLLLLLI-LLLLLLL.-LLLLLLLLLLLLLLLLLLLLLLLLLLL

11、-LLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLL_L_LLLI_LLLLL_L.LLLLLl_LLl_LLL_L-LLLLLLL-LLLLLLLLlllllll-LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLL卵石层胜我在5.2.3-5黏土施打步骤5：成孔(1)钻孔作业应分班连续进行，不得中断。遇有问题，应立即处理。(2)经常对钻孔泥浆进行试验，检查泥浆的主要指数，不合要求时，随时改正。泥浆池-LLLLLLLLLLLLLLLLLLLLLL

12、LLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLLIaLL 口 I I I I I I 1 I I I I I I I I I I I I I I I / ,L-LLLLLLLLLLLLLLLLLLLLLLLL -LLLLLLLLLLLLL

13、LLLLLLLLLLL-LLLLLLLLLLLLLL LLLLLLL -LLLLLLL , LLLLLLLL卵石层曲胜在_LLL_LLLLl_i_ I-I_Ui-i_i_i_LLLLLLLL -LLLLLLLLLLLLLLLLLLLLLLLL5.2.3-6成孔步骤6：清孔。清孔后，泥浆的相对密度宜控制在1.031.10,对冲击成孔的桩可适当提高，但宜不超含砂率宜小于2%,胶体率宜大于98机 孔底沉淀厚度应不过1.15,黏度宜为1720Pas,大于设计规定。泥浆油黄河_L_l_L_l_1_1_1_1_1_1_1_1_1_1_l_L_l_l_l_L_L_1_1_-LLLLLLLLLLLLLLLLL

14、LLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLL.L.-LLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLLLL.LLLLLLLLLLLLLLLLLLLLLLLLILL_L_l_L_L_LL-1-(-(-LI-L-L-L-L-LL.-LLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLL-LLLLLLL一LLLLLLLL-LLLLLLLTPrLLLLLLLL-LLLLLLLJ/H层LLLLLLLL-LLL-L-LLL一LLLLLLLL_LLLLLLLi_i_i_i_i_i_j_i_i_LLLLLLLL-LLLLLLLLLLLLLLLLLLLLLLLLIiiiiiiiiiiiiiiiiiiiiiii5.2.3-7清孔步骤7：下钢筋笼。(1)钢筋笼纵向每隔4m设置一道耳朵形定位筋，沿钢筋笼四周等距布置。(2)桩基主钢筋连接采用机械套管连接的方式，连接前，必须将钢筋头磨平，连接后,外露