Gravel Stratum Of Earth Pressure Balance Shield Construction Surface Subsidence Analysis And Control

Shield tunneling is one of the excavation methods.Compared with other excavation methods,it has many advantages,such as good selfstability and less disturbance to the ground.Shield tunneling method has become a primary method in underground excavation with its predominance,earth pressure balanced shield tunneling is the most universal type in our country,with a vast territory and the complex distribution of stratum,It is the first case of subway builted in the grit&pebble stratum's ground,The key to the construction of the subway is to balance the earth Pressure,and it is important to predict and control as a result of surface subsidence caused by the excavation.Based on the background of Honghu North Road-Zhonggong Road part of Shenyang No.1 Metro。According to the data gathered,the disturbance characteristics of the surrounding soil lead by the construction of shield were analyzed.The detailed works are as below.(1)Considering the characteristics of the grit&pebble stratum's ground, representative data of the ground settlement were chosen to analyze the ground settlement's time and spatial distribution regularities.Afterwards,the characteristics of the grit&pebble stratum's ground settlement,compared with the settlement data of clay stratum were specially expatiated.The formula of Peck is valid on condition excavating in the the grit&pebble stratum(2)The theory Analysis of the pressure balance and the cause influencing the pressure balance in the excavatation solution is discussed,and suming up the way to predict earth pressure in the shield construction what'more,it analys the relation between the earth pressure and the ground settlement.(3)Through the analysis of synchronized grouting and second grouting,the afect of grouting in the ground settlement is clear,so the more effective control measure was built (4)From the example of Honghu North Road-Zhonggong Road part of Shenyang No.1 Metro,it is easy to understand the process of ground surface settlement caused by shield tunneling and the influences of the shield grouting.finally the methods controlling the ground settlement are obtained.(5)Through the entire organization of construction,we represent the consrruction risk analysis and the solution excavating in the the grit&pebble stratum.we also need to take measure to formulate an appropriate plan in important areas,in order to make sure the security of the construction.