Analysis Of Strong Water-rich Layer Comprehensive Pipe Gallery Excavation And Dewatering

As a key construction project launched by the state in recent years,the municipal pipeline integrated pipe gallery is an important step that China has learned from foreign cases in urban infrastructure construction.Planning and making good use of the urban underground space can effectively enhance its integrated carrying capacity and meet the basic needs of the people's life,and can effectively promote economic investment and improve the quality of urbanization under the premise of long-term planning.New impetus to economic development.In recent years,more and more attention has been paid to it.Most of the pipe gallery is built in the center of the city,and the surrounding environment is complex.The key problem in the construction process is the support of the foundation pit.Taking the comprehensive pipe gallery of Qingshan road as an example,the structure of pipe gallery excavation are described in detail,and the comprehensive pipe rack foundation pit dewatering and drainage measures and deployment of construction and operation are described,a plurality of monitoring points are arranged at the scene,a number of projects pile top horizontal and vertical displacement monitoring,monitoring results and theoretical calculation were compared,obtained the following conclusions:(1)Through the discussion of the foundation pit support of the comprehensive pipe gallery,combined with the comprehensive example of the foundation pit of the comprehensive pipe gallery in Qingshan road,from the pipe gallery structure,the proposed site engineering geology,hydrological conditions,the surrounding environment and other comprehensive analysis,selection of safe and economical support scheme.For the surrounding environment is complex,no slope space of the comprehensive pipe gallery foundation pit support recommend Larson steel sheet pile+ steel support and concrete filling pile + steel support,concrete filling pile +concrete support support.(2)Based on the analysis of different supporting forms,it is clear whether additional watertight curtain is needed.Larsen steel sheet pile can also be used as ahanging water stop curtain.Although the seepage flow rate is not obvious,it can effectively increase the seepage path,so as to achieve the effect of water stop.If bored pile support is applied,the three axis mixing pile can be applied to the impervious layer at the interval of piles to play the role of the bottom mounted water stop curtain,which can obviously reduce the seepage flow rate.The effect of precipitation on the settlement of roads and the vertical displacement of buildings can be effectively controlled by the precipitation of water stop curtain.It provides a reference for the water stop of the following foundation pit engineering.(3)For the surface water such as rainwater in the foundation pit,the drainage ditch and the water collecting well can be combined to play the role of drainage and drainage;For the underground water in the pit,need to set the dewatering,the underground water level observation well and relief wells in pit in precipitation and water with precipitation,has played a good role.(4)Based on the pipe rack foundation pit supporting pile top horizontal displacement monitoring,real-time understanding of excavation quality,and monitoring results and calculation results,Tongji QIMINGXING software of PLAXIS finite element analysis results show that the monitoring results were less than the calculated data,Tongji Venus reserve enough safety software for the design of foundation pit support.