Application Research Of Rubber Sand Vibration Isolation Barrier Under Subway Vibration

Subway plays an important role in alleviating ground traffic congestion,but subway vibration has a serious adverse impact on the physical and mental health of residents along the line and the precision instruments of scientific research institutions;In addition,the output of waste tires in China has ranked first in the world,making it one of the main wastes faced by our society.Therefore,how to effectively reduce the environmental impact caused by subway vibration and reasonably recycle waste tires has become a serious topic.Reducing the vibration caused by subway operation and setting vibration isolation barrier is a more effective method.At the same time,the rubber-sand formed by mixing rubber particles and sand made of waste tires through physical processing is an important way to solve the waste of resources in engineering construction.Moreover,the rubber sand has the characteristics of low shear modulus and high damping ratio,which is conducive to give full play to its vibration reduction and isolation performance,Therefore,this paper applies rubber sand to the vibration isolation barrier under subway vibration,and studies the static and dynamic properties of rubber sand as subway vibration isolation material and the vibration isolation law of rubber sand barrier under subway vibration.The research contents and main achievements of this paper are as follows:1.The static and dynamic properties of rubber sand are studied through triaxial consolidation drainage test and bending element test.The results show that under a certain effective confining pressure,with the increase of rubber content,the stress-strain curve gradually changes from strain-softening type.Transform into strain hardening type,the initial modulus of rubber sand decreases,the mixture gradually changes from strain-shear-dilatancy type to shear-shrinking type,the failure deviatoric stress and internal friction angle decrease,the shear wave velocity (1,the maximum shear modulus shows a downward trend;under a certain rubber content,with the increase of effective confining pressure,the initial modulus of rubber sand increases and the shear shrinkage characteristics are more obvious,and the shear wave velocity (1 and the maximum shear modulus increase.2.Through the drop weight impact test,the vibration isolation law of rubber sand under impact load is studied.The test results show that the vibration isolation performance of rubber sand is better with the increase of rubber content and thickness;When the rubber content is20%,the optimum thickness of rubber sand with 100 mm thickness is summarized.3.Through midas gts nx finite element software,the finite element model of subway train track tunnel soil layer vibration isolation barrier is established,the vibration isolation law of rubber sand barrier under subway vibration is studied,the vibration isolation law of rubber sand barrier under foundation soil type（hard soil,medium hard soil,medium soft soil and soft soil）,depth,width and position are considered,and the vibration isolation law of empty ditch barrier is compared.The results show that the vibration isolation effect of empty ditch is the best in any foundation soil;The isolation effect of rubber sand barrier in hard soil is the best,and the vibration isolation effect is concentrated in the range of 30～60Hz frequency band,and the ratio of 30% is better than 0% rubber sand,and the wave resistance ratio is introduced to explain;When the barrier depth of rubber sand and empty ditch barrier is greater than 12 m,increasing the barrier depth h can not effectively increase the vibration isolation effect;For the hollow ditch barrier,the vibration isolation effect of the barrier does not change significantly with the increase of the width.For the empty ditch barrier,the vibration isolation effect of the barrier does not change significantly with the increase of the width.For the rubber sand barrier,increasing the width w of the barrier makes the vibration isolation effect better.The simplified vibration isolation expressions of the average amplitude attenuation coefficient of empty ditch and rubber sand barrier are summarized as follows:（?）=0.212H^-0.84、（?）=L_sL_a = 0.212.and = .