綜合管溝基坑支護技術(shù)交底.doc

交底內(nèi)容：
1. 對實際開挖深度≤3.0m的基坑，采用自然方坡的方法，放坡系數(shù)為1：0.5～1：1，主要是針對土質(zhì)好地段，坡面抹5.0cm厚C15混凝土，防止雨水沖刷。在K6+950～K8+075里程范圍，路基雖然已采用軟基處理，但淤泥層厚，樁身強度較差，靠外側(cè)通車道一側(cè)采用拉森鋼板樁支護，樁長度不小于9.0m，路堤面用水泥砂漿抹面硬化坡面。
2. 對實際開挖深度≤5.0m的基坑，針對較好土層，上面1.2m采用1：1放坡，坡面噴射C15混凝土硬化層，下面采用拉森鋼板樁疏樁支護（間隔施插）；若遇到相對較差土層，采用密排拉森鋼板樁支護。鋼板樁頂設(shè)一道支撐，支撐選用32號雙翼工字鋼。在K8+075～K8+375、K8+460～K8+850、K9+075～K9+209及K9+600～K9+700里程范圍，主要為開挖段，開挖深度為4.0～4.5m，從現(xiàn)場開挖的土質(zhì)分析來看，為硬塑狀粘性土，可采取以上支護形式。
3. 對實際開挖深度＞5.0m的基坑，采用密排鋼板樁支護，樁頂以下0.5m設(shè)一道支撐，支撐選用32號雙翼工字鋼，水平間距不大于4.0m。
4. 施工過程中要加強對基坑的監(jiān)測，每隔20.0m設(shè)一個沉降和位移觀測點，發(fā)現(xiàn)有異常情況時及時采取應(yīng)急處理措施，如采取回填反壓土或坑頂卸土的方法。
基坑降水采用井點降水，保證水位在坑底以下0.5m；施工過程要
Cards on the table contents:
1. On the actual excavation depth ≤ 3.0m of the pit, using the methods of natural side slope, up slope coefficient was 1:0.5 ~ 1:1, mainly for soil good location, slope wipe 5.0cm thick C15 concrete, to prevent rain erosion. In the K6 +950 ~ K8 +075 mileage range, although the use of soft subgrade treatment, but the silt thickness, shaft strength less, by using the lateral side of the opening of Tao Larsen Steel Sheet Pile, pile length is not less than 9.0m, embankment surface finishing with cement mortar hardening slope.
2. On the actual excavation depth ≤ 5.0m of the pit, for the good soil, 1.2m above the 1:1 cut slope, slope jet C15 concrete hardening, the following sparse pile with Larsen sheet pile support (interval Shi interpolation); If they are in relatively poor soil, using closely spaced steel sheet pile retaining Larsen. Set up a steel sheet pile head support wings 32, I-beam support used. In K8 +075 ~ K8 +375, K8 +460 ~ K8 +850, K9 +075 ~ K9 +209 K9 +600 ~ K9 +700 and mileage range, mainly excavation section, excavation depth of 4.0 ~ 4.5m, Excavation of soil from the site of view, the hard plastic clay, may take the form of more support.
3. On the actual excavation depth> 5.0m of the pit, using closely spaced steel sheet piles, pile top the following set up a 0.5m support wings 32, I-beam support used, the horizontal spacing of not more than 4.0m.
4. The construction process to strengthen the monitoring of the pit, every 20.0m set up a settlement and displacement of observation points, found that there is abnormality in a timely manner to take contingency measures, such as taking anti-compacted soil Huo pit backfill the top method of dumping soil.
Foundation pit with well point dewatering, the water level in the pit bottom to ensure the following 0.5m; the construction process to
 

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