| The excavation and precipitation of large foundation pit have been an important part of geotechnical engineering,its technical complexity and strong systematicness,the excavation and precipitation of the foundation pit can be better handled,can greatly improve the quality of construction projects,and reduce the related engineering accidents.The foundation pit excavation precipitation problem covers many aspects such as safety,economy,environmental protection construction quality and so on.Moreover,in the East Route Project of South to North Water Transfer,the construction of Beijing Hangzhou and the Grande Canale is increasing,the scale of construction is becoming larger and larger,and the engineering geological and hydrogeological conditions are becoming more and more complex.Therefore,it is very important to understand the engineering geological and hydrogeological conditions of foundation pit,and the design,construction and key of the excavation of large foundation pit on the basis of surrounding environment and site.At the same time,the technology of foundation pit excavation and precipitation under large and complex geological conditions has been concerned about geotechnical engineering both at home and abroad.Consequently,based on the excavation of the deep foundation pit of Shiqiao Three Line Shiplock in Yangzhou,the following research works are carried out:1.In order to make the construction designers understand and master the geological condition of the construction site in detail,the engineering geology of the area is divided into 12 layers in the depth of exploration,of which there are 3 sublayers in third layers and 2 sublayers in the fourth layer.The 12 layers are not distributed in the same section.The distribution of the 12 layer is not in the same section,in the upstream channel in eight different geological layer,in a boat and the upstream upstream approaches,there are seven different geological layer,ship lock working bridge has nine different geological layer,lock in nine different geological layer.2.The foundation pit excavation site is large,in order to facilitate the design and construction of the super foundation pit dewatering support under the condition of the water rich interbedded land,on the basis of the geology and hydrogeological properties of the project,the concept of excavation and dewatering of the foundation pit “larger,smaller and lesser” was adopted,combined with the lock foundation pit excavation depth and precipitation supporting characteristics of ship lock excavation can be divided into upper and lower lock heads and the east,the west side of lock chamber,the brake pond and so on five big part of the excavation support.The top sluice head mainly adopts the reinforced concrete continuous wall structure,which can play the dual effect of retaining and seepage prevention,the rest are single row and small diameter cement mixing pile wall,and the gate and pond are divided into step type ladder type excavation.3.The anti-seepage wall of the east side of the gate and the Central Line of the lower gate is proposed.The lower gate is in the water-rich interlayer soil and the anti-seepage curtain depth is more than 21 m.In the west side of the gate and the west side of the lower gate,a single row of small diameter puddle is used to prevent the seepage wall.4.Through to the Beijing-Hangzhou grand canal locks rich water alternating layers soil excavation as the research background,aiming at this kind of complex geological condition of excavation,expounds in detail the key of draining water and the key technology of foundation pit supporting calculation analysis,at the same time,the seepage prevention curtain workers with multi head small straight diameter and high pressure shimmy combination are adopted.Art for the first time,with certain engineering characteristics,accumulate reliable experience in engineering practice,for future similar geological conditions to provide effective reference or reference for foundation pit excavation. |
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