TBM Construction Technology And Performance Test In Xinjiang Super-Long Tunnel With"Two Tbms One Inclined Shaft"

With the rapid development of Chinese economy,large-scale infrastructure construction is required,and different types of long tunnels need to be excavated.Due to the consideration of construction period,environmental protection and safety,traditional drilling and blasting method has been difficult to meet the construction requirement.The construction technology of full section tunnel hard rock boring machine(TBM)can not only achieve higher tunneling speed,but also be safer and more environmentally friendly than drilling and blasting method.In this paper,XinJiang EH diversion project KS super-long tunnel as the background,the project for the first time using two TBMs one inclined shaft" TBM construction method.The performance of TBM is tested and analyzed with the data collected on site.The main research contents and achievements of this paper are as follows:①The type and design of TBM was analyzed according to the engineering background.The technical proposal of" two TBMs one inclined shaft" TBM assembly and construction layout is presented based on the consideration of Two TBMs share the assembly chamber with coordinated rapid installation,cave assembly and construction operation layout.Field application tests show that:TBM2 adopted the assembly scheme of "assembling while stepping and then debugging,which lasted 63 days.TBM3 adopts the scheme of "simultaneous assembly at the beginning and end"and then step by step and debug",which takes 39 days to complete the assembly task efficiently and quickly.The installation of two TBM continuous belt conveyors,mixing station and inclined shaft fixed belt unit lasted for 30 days.The two TBMS Shared 146 d from assembly to tunneling.During the normal tunneling of TBM,the monthly TBM tunneling delay of the concrete batching station installed in the assembly hole accounts for less than 1%;The installed material transport system accounts for about 2%of tunneling delays per month.②The two TBMs one inclined shaft" TBM mucking out technology are studied,according to the construction background,the mucking out scheme in primary hole and the inclined shaft has carried on the comparison.The technical scheme of two TBMs in reverse tunneling with a continuous belt conveyor and a fixed belt conveyor with one inclined shaft for mucking out is put forward.Analysis of tunneling parameters obtained on site shows that:the installation and arrangement of belt conveyor are reasonable,the traffic volume and the belt speed meet the requirements.After the statistical analysis of the failure of the slag discharge system of the belt conveyor,it show that the tunneling time delay of the continuous belt conveyor per month is 1%～2%,and the tunneling time delay of a single TBM per month for the fixed belt conveyor in the support hole is about 2%.It shows that the slagging system of belt conveyor used in this project is safe and reliable.Two TBMs share one inclined shaft belt conveyor for mucking out,that did not increase the tunneling delay time of each TBM,which provided a reference basis for the selection of TBM slagging scheme in Inclined Shaft with "two TBMs one inclined shaft" in the future.③According to the supporting project "two TBMs one inclined shaft",the quantity of two TBM cutters is different.Through field test and analysis,this paper studies the influence of differential knife spacing on TBM tunneling performance,and the results show that:In the Ⅲa rock type of sandstone with the compressive strength of saturated between 50～70 MPa,the penetration,driving speed and the energy consumption of TBM with different cutter spacing don’t have too big difference,under II class surrounding rock,the compressive strength of saturated between 70～90 MPa,the penetration,driving speed and the energy consumption of TBM with different cutter spacing don’t have too big difference too,but under different the cutter spacing can change parameters of optimal excavating in minimum energy consumption,when the disc cutter speed is 7 r/min,the optimal penetration of TBM with 78 mm cutter spacing is 8.5 mm/r,The optimal penetration of TBM with 75 mm cutter spacing is 10 mm/r.④Based on " two TBMs one inclined shaft" TBM performance on the field test and statistical analysis found that:the TBM excavates in the sandstone rock,month footage can reach 650 m or so,in the II class surrounding rock under high speed of 47.78 m,daily average speed of 27.54 m.IV class surrounding rock under the daily average speed of 14.19 m.TBM tunneling under granite surrounding rock,monthly footage is about 350 m,maximum daily footage under granite surrounding rock is 27.08 m,average daily footage is 11.07 m.The average monthly tunneling utilization for both TBMS was 28%.The highest equipment completion rate of TBM in a single month can reach 90.19%,and the monthly equipment completion rate is maintained between 70%and 90%.Through the design of test scheme and data collection analysis,it is found that there is a good linear correlation between TBM tunneling parameters,but the fitting relation between tunneling parameters will change with the change of surrounding rock lithology,surrounding rock category and cutter head speed.