Underground lifeline engineering(ULE for short)in modern city demands the ap-preciation of an active fault in buried bedrock.Generally speaking,a large numberof urban geological textures of a basement may all be simplified into a dual geologicaltexture model,i.e.,the upper part of the basement consists of loose covering layerand the lower part consists of bedrock.The study of an active fault should includethree parts of contents,i.e.,to determine the lower time limit of activity of thefault,and the time limit must be recognized by both of designing engineers and geolo-gists;on the basis of the studies of repetition periods of earthquake occurrence to deter-mine whether the fault moves or not during the allowed time of efficacy of buildingsand constructions;for the sake of engineering practice,the active rate of the faultmust be given.The fault with different active mechanism has different effects on theULE.The authors studied the effect of lateral non-uniform overburden site on theULE by means of the su 相似文献
Earthquake response of underground lifeline engineering is investigated by the method of ultrasonic model experiments in this
paper. From general field conditions, two models of underground lifeline engineering, one for non-uniform field and the other
for uniform field, are designed based on the similarity principle. Besides analysis of seismic phases, a series of analyses
especially on particle vibration are carried out. The results show that:
The shorter the epicentral distance, the greater are the intensity variation and the change rate of intensity variation of
earthquake ground motion, so the more disadvantageous to underground pipelines. In soft covering layer, compressional waves
mainly cause radial flexures deformation, but shear wave result in axial dilation deformation of the pipelines; when the thickness
of the covering layer is smaller (less than seismic wave length), the rhythmic variation of the intensity of earthquake ground
motion is controlled mainly by the wave length of seismic waves in the bedrock. The property of the covering layer has considerable
effect on earthquake ground motion. For different covering layers, their effect on each component of earthquake ground motion
is not the same.
Owing to the effect of wave propagation, the ground is in different states of particle vibration at different times, and there
is considerable difference in phase and intensity of particle vibration between two different covering layers near their junction
line or surface. Because underground lifelines tend to vibrate with the particles of the earth around it, this results in
different deformation of underground pipelines under different conditions. So, it is necessary to take corresponding anti-seismic
countermeasures for pipelines according to their practical situations.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 104–110, 1992.
This paper is part of the research supported by Funds of Doctoral Faculty of National Education Committee. 相似文献
To compare the rock breaking performances caused by the arc and wedge hob with two blades, a rock cutting model with two hob blades is established and a series of rock cutting simulations are performed based on the particle flow code. Meanwhile, the rock breaking process, crack extension pattern, rock cutting force and rock cutting efficiency etc. are investigated in this study. The results present that the rock breaking area and the lateral crack length induced by the arc blades is much greater than that induced by the wedge blades. The optimal cutting spacing of the arc and wedge blades is 60 mm and 30 mm respectively. It confirms that the wedge blades can significantly reduce the rock cutting force and raise the rock cutting efficiency compared with the arc blades, which can provide a reference for the hard rock tunneling by the tunnel boring machine.