Study On The Effect Of Ring-Shaped Trench Barrier On Vibration Wave In Layered Foundation

With the improvement of the economic level,the development of urbanization in my country is getting faster and faster,and the scale of construction is getting larger and larger,which brings great convenience and also brings some adverse effects,among which the most significant impact is artificial vibration.,For example,the artificial vibration generated by piling,blasting,rail transit and mechanical operation has large impact and strong persistence,which greatly affects the production and life of nearby residents.threat.Based on this phenomenon,relevant research on how to effectively reduce the impact of vibration is of great significance.in this thesis,the layered foundation ring trench is used as a continuous vibration isolation barrier.Field tests have been conducted to explore the impact of changes in geometric parameters such as depth,width,and center angle of the ring trench barrier on vibration waves when the surrounding directions are different.The barrier effect of the layered foundation is refined,and the location area of the interface of the layered foundation is refined.When the depth of the annular trench reaches near the interface,the change law of the barrier effect of the annular trench on the vibration wave is explored,and then the finite element method is adopted through COMSOL.Establish a ring-shaped trench vibration isolation model with the same size as the field test for analysis,and compare the analysis results with the field test law to verify the effectiveness of the finite element method.A full-size layered foundation ring-shaped trench vibration isolation model is established with the depth of the ring trench,Width and central angle parameters are variables for linear analysis,complementing each other with the field test rules,and the main conclusions are as follows:(1)In a homogeneous,double-layered soil foundation,under the same parameter conditions,the vibration isolation effect of the annular trench in the homogeneous foundation soil is better than that of the double-layer foundation soil;there are vibration enhancement areas in front of the positive annular trench and at the end of the trench.The end area of the groove continues to attenuate with the increase in the depth and central angle of the forward annular groove,and the attenuation rate continues to increase.With the continuous increase of the width of the forward annular groove,the vibration strengthening zone also continues to attenuate,but the attenuation rate is fast It is related to the vibration source distance,the smaller the vibration source distance,the faster the attenuation rate.(2)Under the vibration isolation conditions of the forward and reverse annular trenches in the layered foundation,the depth parameter is an important parameter that affects its vibration isolation effect,and the greater the depth parameter,the better the vibration isolation effect,but when the depth of the annular trench is close to When the upper soil is thick,the effective vibration isolation area is relatively scattered,and the proportion of the effective vibration isolation area increases slowly with the increase of the depth parameter,and its vibration isolation effect is relatively weak.Therefore,in the vibration isolation design of the ring trench of the layered foundation,It is recommended to increase the depth parameter and try to avoid excavation to the interface of the soil layer.(3)Under the vibration isolation condition of the forward and reverse annular grooves in the layered foundation,with the increase of the width parameter,the effective vibration isolation area behind the annular groove changes very little.It can be seen that the width parameters of the forward and reverse annular grooves These are not important parameters that affect its vibration isolation effect.Therefore,in the design of ring-shaped groove vibration isolation,considering the economical application,it is recommended to set the ring-shaped groove to a smaller value;the center angle and arc length parameters of the ring-shaped groove affect its isolation.Important parameters of vibration effect,and the larger the central angle and arc length parameters,the better the vibration isolation effect.Among them,the influence of arc length parameters on the vibration isolation effect in the reverse annular groove vibration isolation effect is found,when the arc length parameter reaches 2.2 In the future,the vibration isolation effect tends to be stable,so in the reverse annular groove vibration isolation design,it is recommended that the arc length parameter be set to about 2.2.(4)The finite element analysis method has been well applied,and it is concluded that the regular trend is basically consistent with the field test results,and the effectiveness has been verified.It can be applied to the study of the ring-shaped trench vibration isolation of the full-size foundation model,and it is found that the full-size layer The finite element analysis results of ring-shaped ditch vibration isolation of the ground-shaped foundation are basically consistent with the trend of the field test response law.