Study On Shield Construction Analysis For Anhydrous Sand Stratum In Xi'an Metro

In the construction of the domestic shield,when the shield passes through the full-face sand,the ground settlement is not easily controlled due to the instability of the water-sands sand,the large settlement on the ground,and the collapse even in severe cases.In addition,due to the stratigraphic characteristics of the sand layer and the large frictional resistance between the particles,the abrasion of the shield cutter is rather large and the configuration of the cutter is unreasonable.Therefore,the shield construction will be difficult to implement.At present,there are few researches on tunneling parameter control and slag improvement effect of shield machine in the waterless sand layer at home and abroad.Therefore,it is of high practical value to study the shield machine and the cutter plate selection of sand stratum.How to control the parameters of the shield machine when crossing the full section of the sand bed in order to realize smooth tunneling and settlement control.In this paper,the first sub-project of Xi'an Subway Line 1 and the shield tunnel between Zhangjiacun Station and Houweizhai Station are taken as the research background,and the whole section of the sand section is selected as the research object.The construction conditions,engineering geology and hydrogeology of the project are selected Factors,such as selection of earth pressure balance shield machine,cutterhead configuration,shield construction process,control of excavation parameters and improvement of muck.According to the characteristics of anhydrous sand layer,considering the advantages and disadvantages of earth pressure balance shield and mud-water balance shield,the former is selected as the shield machine for construction.After the parameters of the relevant parameters are rationally allocated,the parameters such as the thrust,torque,amount of excavation,the amount of synchronous grouting and the effect of slag improvement when the TBM traverses through the full-face sand are statistically analyzed.Combined with the monitoring results of surface subsidence Data,analyzed the relationship between the ground settlement and tunneling parameters during tunneling,determined the ratio and reasonable dosage of slag improvement,verified and perfected with the engineering practice,so that the shield The machine safely and smoothly passes through the stratum and has obtained some economic benefits,so as to solve some problems of the shield machine traversing the waterless sand layer,which can provide some experience for the construction of similar stratum in the future.