排水沟槽开挖、回填技术交底.doc

交底内容：
一、土方开挖：
1.  测量放样定出中心桩、槽边线及堆土堆料界线，界线至开挖线的距离应根据开挖深度确定，并不小于5m。
2.  开挖前，先查明段地下管线及其它地下构筑物情况，会同有关部门做出妥善处理，确保施工安全。并提前打设井点降水，在地下水位稳定在槽底以下1.0m时才进行土方开挖。
3.  采用机械开挖方式为主，人工开挖方式为辅的挖土方式。开挖应分层、分段依次进行，形成一定坡度，以利排水。开挖时不允许破坏沟底原状土，若不可避免沟底原状土被破坏时，必须用原土夯实平整。基底设计标高以上0.2~0.3m的原状土，应在铺管前人工清理至设计标高。
4.  采用放坡开挖，基底宽度为管径加上工作宽度和临时排水沟的宽度。放坡的坡度采用1：1，排水沟的截面尺寸为200mm×300mm，沿着临时排水沟每隔20m设置600mm×600mm×800mm的集水井，采用潜水泵把集水井的水抽出沟槽外。开挖时应保护坡脚，边坡应严格按图纸施工，不允许欠挖和超挖，边坡应用人工修整。
5.  开挖后的土方如达到回填质量要求并经监理确认后应用于填筑材料，不适用于回填的土料弃于业主、监理指定地点。
6.  沟槽开挖时其断面尺寸必须准确，沟底平直，沟内无塌方，无积水，无各种油类及杂物，转角符合设计要求。
7.  开挖沟槽达设计标高时，应立即报监理验收并做土工试验，检查合格后应尽快进行基底垫层施工，以防渗水浸透基底。
8.  基底土质与设计不符时，应报监理、业主研究讨论，由业主、监理、设计和施工单位共同商讨加固措施。
9.  开挖完成后，应及时做好防护措施，尽量防止基底土的扰动，并应尽快组织进行基底垫层施工。
夜间开挖时，应有足够的照明设施，并要合理安排开挖顺序，防止错挖或超挖。
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Cards on the table contents:
1, earth excavation:
1. Survey setting set center pile, heap mound material groove edges and lines, line to line distance of excavation should be determined according to the depth of excavation, not less than 5m.
2. Excavation before the identification section of underground pipelines and other underground structures in the situation, together with relevant departments to make proper treatment, to ensure construction safety. Set in advance to play well point dewatering, the water table stable at bottom only when the following 1.0m earth excavation.
3. Mainly by mechanical excavation, supplemented by manual excavation excavation methods. Excavation should be hierarchical, segmented in turn, a certain slope to facilitate drainage. Not allowed to undermine the ditch excavation undisturbed soil, if the inevitable bottom was undisturbed soil is destroyed, you must use the original soil compaction level. Basal 0.2 ~ 0.3m above the design elevation of the undisturbed soil, should be to clean up before laying pipe to the design elevation.
4. By Slope excavation, base width is the width and diameter with the work of the width of the temporary drainage ditches. Slope gradient of 1:1, the drain section size is 200mm × 300mm, 20m to set up temporary drains every 600mm × 600mm × 800mm set of wells, wells with submersible pumps the water out of Baji outside groove. Excavation should be to protect the foot of the slope should be strictly in accordance with construction drawings, are not allowed due to digging and ultra-digging, artificial slope repair.
5. Excavation to backfill of earth, such as quality requirements and confirmed by the Commissioner of filling material used, does not apply to the backfill soil material abandoned in the owner, supervision and designated locations.
6. Trench excavation size of its cross section must be accurate, the bottom was flat, trench without cave-ins, no water, no oils and debris, corner meet design requirements.
7. Digging a trench up to the design elevation, the inspection and supervision should be immediately reported to do soil tests to check the basement as soon as possible after passing the cushion construction to prevent water seepage soaked basement.
8. Basement soil and the design does not comply, should be reported to the Commissioner, the owners of the discussion, by the owners, supervision, design and construction units to discuss remediation.
9. Excavation is completed, should be protective measures in good time, try to prevent basement soil disturbance, and organizations should base cushion construction.
Excavation at night, should have adequate lighting facilities, and excavation in order to make reasonable arrangements to prevent the wrong dig or over excavation.
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