| with the development of tunnel and underground engineering,more and more underground structures in the process of construction and use,all of which are subject to the hazards of groundwater.Over the years,people in groundwater long struggle with the accumulated rich experience,summed up the "prevent,blocking and cutting combination,adjust measures to local conditions,comprehensive management of the tunnel and underground engineering waterproof principles,tunnel and underground engineering waterproofing and drainage technology with rapid development.Many tunnels and underground engineering requires both structural type of economic and reasonable,and no seepage,leakage,and underground engineering geological conditions is very complex,in the construction process in varying degrees by the groundwater,which requires the design unit reasonable waterproof and drainage design,selection of reasonable selection of structure type,reasonable waterproof and drainage methods and materials,so as to achieve the good technical and economic benefits.Domestic currently under construction or have been built Metro City,the majority of soil stratum,in view of the soil of strong permeability and drainage caused by the environmental impact is bigger,so the all inclusive waterproofing systems,and code for metro design is mainly based on geological layers of urban subway construction experience written,clear requirements and giving priority to prevention.However for the city like Qingdao,Chongqing geological rock based and stratum water content and permeability coefficient are small,if still in accordance with the rules and traditions of the waterproof model of structure(structure outside waterproofing design,consider the head pressure),has been outdated.According to the actual situation,Qingdao Subway Line 3 station and tunnel with about 50?60%is located in?in weathered rock,rock integrity is good,crack not development,and underground water for the poor?extremely deficient,water inflow in tunnel and underground engineering is small,with set drainage tunnel,waterproofing and drainage water tunnel and permanent bolting and shotcrete lining the possibility of binding.So in order to make full use of the geological characteristics of hard rock in Qingdao area should be to seek a reasonable structure type and waterproof and drainage project,so as to reduce the engineering quantity,reduce the project cost,achieve good technical and economic benefits.Therefore,according to the defects of the geological characteristics of Qingdao area and domestic subway related specifications,develop the application in Qingdao Subway Stations and in the tunnel is safe,reliable,economical and reasonable,good durability,maintenance of anti drainage system is a priority.The waterproof and drainage system has the characteristics of multiple protection,safety and reliability,at the same time,with the maintenance of the post operation period.Based on this,this article through the theoretical analysis,numerical simulation and field measurement and other means,the rock stratum tunnel waterproofing and drainage system has been studied,the main conclusions are as follows:(1)the comprehensive consideration of rock quality index,joint,joint roughness,joint alteration,water and ground stress of six factors,the Q system classification of surrounding rock of surrounding rock of tunnel regulation law of the people's Republic of China the basic classification of re classification.By comparing the calculated level I rock tunnel regulations contains Q 1 to 8 of the surrounding rock,surrounding rock grade II contains Q 1?9 class surrounding rock,grade III rock contains Q 1?9 class surrounding rock and IV rock contains 4-9 Q system of surrounding rock and V-grade surrounding rock contains Q system 7-9 class surrounding rock.In view of the actual situation of Qingdao Metro Line 3 for detailed classification,for each level of surrounding rock to take corresponding earthly support measures,the factors to consider more comprehensive,combined with the actual geological conditions more closely.And the support measures based on the surrounding rock classification of Q system can match with the actual geological conditions,and the selection is more flexible and workable.(2)based on the theory of groundwater dynamics,the seepage analysis model suitable for the underground tunnel of the mine is more suitable for the actual engineering situation.Through the practical engineering verification,the model has good accuracy and strong practicability,and it is more convenient for engineering and technical personnel to use.Compared to the previous traditional tunnel gushing calculation formula,the study comes to the conclusion that the formula give full consideration to the differences in rock and soil media,models also distinguish diving layer model and the crack formation water model,the seepage flow rule of the model more in line with the actual situation.(3)of steady phreatic aquifer layer characteristic analysis based on,innovative proposed formula of equivalent permeability coefficient method,the method will soil as a stable water,soil is not involved in the equivalent permeability coefficient calculation and through the engineering practice verify the method is reasonable.At the same time,the theoretical formula in spite of circular model derived from,but in low head(metro tunnel),the tunnel water inflow in the sensitivity of various shapes is not strong,in the different shapes of the tunnel analysis are derived for the numerical difference.Therefore,formula for low head of metro tunnel is fully applicable.(4)the grouting of surrounding rock of tunnel has a great influence on the water inflow of tunnel,but also has great influence on the design of the water drainage system of the tunnel.Simple wall rock grouting,although can achieve the purpose of water plugging,but does not guarantee the safety of lining structure.In lining completely blocked,and in the surrounding rock does not exist seepage,regardless of the permeability coefficient of surrounding rock,grouting circle size,behind the lining ultimately bear the hydrostatic pressure;when the memory of surrounding rock in seepage field and in surrounding rock of the tunnel with head loss,behind the lining water pressure is slightly small than hydrostatic pressure.Therefore,the waterproof and drainage of the tunnel should adopt the principle of"to block the main and limited emission",to take practical and reliable design and construction measures,to achieve the purpose of waterproof,reliable,drainage,economic and reasonable.According to the different parameters of grouting tunnel under the condition of seepage flow and water pressure of grouting circle. |
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