Study On The Mechanism And Effective Influence Distance Of Ground Fracture In Xi'an

The development of ground cracks has a serious impact on the life of modern human beings.Urban subway,rail transit,road and bridge,house construction and other aspects should be restricted by ground cracks.With more and more attention being paid to the ground fracture activity,people's research on the ground fracture is more and more inclined to change from the origin mechanism of ground fracture activity to the mechanism of ground fracture destruction.At the same time,since the introduction of Hei he river water and the restriction of underground confined water exploitation in xi 'an area,the rate of ground fissure activity in xi 'an area has gradually decreased.However,in xi 'an area,the safe distance of ground fissure is still used at the peak pumping time,so it is very necessary to study the relationship between the active rate of ground fissure under different pumping action and the effective influence distance.With the rapid development of xi 'an city,the generation of large area building load has created a new settlement funnel in xi 'an city,and the influence of building load on ground crack has also become the focus of attention.This article mainly through to the xi 'an analysis of geological environment and development situation of xi 'an ground fissures,combined with the research of xi 'an ground fissure extension way,the fields of confined water and extracting underground building load activity mechanism of cracks are analyzed,at the same time using the Basinesk solution is put forward to solve the uneven settlement of surrounding soils ground fissure approach.FLAC3 D software was used to simulate the extraction of underground confined water and the influence of building load on ground crack activities.On this basis,the ground fracture activity rate and its corresponding effective influence distance are explained by theoretical analysis and numerical simulation.At the same time,the accuracy of the simulation results is verified by the groundwater extraction and ground subsidence monitoring data combined with field investigation.And to the safety of the specification of the distance to avoid the optimization.And draw the following main conclusions:1.The artificial extraction of underground confined water will not only lead to the vertical deformation of the pumping area,but also cause the horizontal movement of the aquifer.Under the action of building load,the buildings around the ground crack will have uneven settlement.The Basinesk solution method can be used to obtain the additional stress under the action of different building loads,so as to further calculate the uneven settlement around the ground crack.2.According to the simulation,compared with the extraction of underground artesian water,the influence of building loads on ground cracks in a large range is less.At the same time,in the process of extracting underground artesian water,it is found that the main factor affecting the ground fracture activity is the amount of underground artesian water extracted,which has little relation with the extraction rate.3.According to the simulation of different pumping volumes,with the increase of pumping volumes,the activity rate of ground fractures increases,and the effective influence distance of ground fractures also increases,showing a positive correlation.However,with the continuous increase of the pumping water,the effective influence distance will not increase indefinitely,and a stable state will appear when it reaches a certain value.4.The simulation results show that the effective influence distance of ground fracture under different pumping water volume and ground fracture activity rate is as follows: the influence range of the upper plate is large,while that of the lower plate is relatively small.Combined with the ground fracture code,it is concluded that in some areas where the ground fracture activity is slow and the phenomenon of underground confined water extraction is not obvious,the avoidance distance can be reduced appropriately,so as to achieve the purpose of rational utilization of land resources.