新型泡沫剂在土压平衡盾构施工中的研究与应用

摘要

Gravel stratum is of unfavorable plasticity and fluidity,which is sure to bring serious wear of cutter wheel and screw.Moreover,earth pressure balance is not easily maintained and the face is easy to collapse.In view of this situation,A new type of foam used in EPB shield is developed,an experimental study on the plastic flow of a new type of foam modified gravel stratum of Beijing Metro No.16 Xiyuan station to the River Bridge Station is studied.Slump test results indicate that the optimal conditioning parameters to achieve required plastic behavior are w =5％ ～ 12.5％,FIR =20％ ～40％.The shield tunneling experiment was carried out by using the foam agent,the main parameters (earth pressure on the cutter head of 0.45 ～0.55 MPa,torque of 3000 ～ 3750 kN/m,driving speed of 35 ～45 mm/min)show that the new foam can meet the construction needs,greatly improve the efficiency of the excavation.%针对土压平衡盾构在砾砂地层掘进过程中,土体塑流性差,刀盘及螺旋输送机磨损严重,开挖面平衡不易保持等问题,开发了一种土压平衡盾构用新型泡沫剂,以北京地铁16#线西苑站～万泉河桥站区间砾砂地层土压平衡盾构施工为案例,对新型泡沫剂改良砾砂地层的塑流性进行了室内试验研究,得出含水率为5％～12.5％,泡沫掺量为20％ ～ 40％时,土体塑流性良好.利用该泡沫剂进行了盾构掘进试验,改良后刀盘上土压力主要集中在0.45 ～0.55 MPa,扭矩在3000～3750 kN/m,掘进速度在35 ～ 45 mm/min之间,结果显示,新型泡沫剂能满足施工需求,大大提高了掘进效率.