硬粘土中高压淹没水射流破土实验研究

Experimental Research on High-Pressure Submerged Water Jet Trenching Stiff Clay

射流破土的关键因素均进行了模拟,包括土体强度、喷嘴直径、射流压力、喷嘴移动速以及喷嘴距离土体表面的距离。其中土体强度通过在天然粘土中添加水泥配制,设计强度约150 kPa。喷嘴移动速度则是通过制造一套直线导轨进行控制。研究发现通过配制人造粘土进行实验是可行的,可以降低天然粘土不均匀带来的误差,提高实验精度。实验还发现,10 bar左右的射流压力对150 kPa左右的硬粘土开沟极为困难,开沟速度28~252 m/h时12 bar压力时开沟深度约为喷嘴直径5~9倍(最深14.4 cm)。喷嘴与土体表面距离对开沟深度有很大影响,当喷嘴距离土体表面从0增加到8倍喷嘴直径时,开沟深度下降为原来的27%。

All key parameters involving water jet trenching soil are simulated,which include clay shear strength,water jet pressure,diameter of nozzle,nozzle traveling speed,and the distance from nozzle to soil surface.The design intensity of soil body can reach 150 kPa by adding cement into natural clay.The travelling speed of nozzle can be controlled by using a linear guide rail.It is disclosed that the artificial clay applied in the test can reduce the error coming from uneven natural clay and improve the testing accuracy.Approx.10-bar water jet pressure is hard to trench the stiff clay with the intensity of 150 kPa.Based on the trenching speed within the range of 28~252 m/h,and the water jet pressure of 12 bar,the trench depth is about 5~9 times the diameter of nozzle,that is,the maximum value of 14.4 cm.The distance from the nozzle to soil surface affects the trenching depth to a high extent.When the above distance increases from 0 to 8 times the nozzle diameter,the trenching depth decreases by 73%.