Research On Hydrodynamic Process Of Response Of Well Water Level Of Confined Aquifer To Cyclic Loading

The interpretation of physical mechanism in aquifer hydrodynamic process under cyclic loading have been one of the hot topics in the joint research of seismic fluids and geotechnical engineering.The core problem lies in the improvement of the quantitative calculation model of the aquifer pore pressure accumulation and dissipation and the further analysis and research of the influencing factors.But because of lacking datas of aquifer pore in site condition,aquifer pore is not observation.Good confining properties Confined wells can sensitively reflect changes in the stress-strain state of aquifers.Therefore,the dynamic change of aquifer pore pressure is reflected by the water level fluctuations in confined wells has theoretical reference and practical significance.This study work can intepretate the physical mechanism of well level change because of seismic wave,also can provide theory reference of geotechnical engineering stability.This dissertation based on the phenomenon of the response of the water level of the confined well to seismic waves,the hydrodynamic process of the response of the water level of the confined well to the dynamic stress of the aqueous medium is studied.And combining the theory of pore elastic stress and strain,Hydraulics theory and seepage mechanics theory.A coupling model of hydrodynamic process for stress-strain-seepage-well flow coupling of water-containing medium for the response of water level in confined wells was established.This model embodies the coupling process of the dynamic stress of water-containing medium and the process of groundwater seepage flow,and the coupling process of groundwater seepage and well flow.This model based on earthquake cases and indoor shaking table tests,the hydrodynamic process is systematically studied.The results of the dissertation are as follows:(1)Taking the response of the water level of the confined well to the seismic dynamic stress as the background,a conceptual system of the response of the aquifer pore pressure and water level of the confined well to the seismic dynamic stress is proposed,and the hydrodynamic process of the response of the confined well water level to the dynamic stress is comprehensively analyzed,and proposed four levels,three links and two coupling processes.(2)Based on the balance of pore elastic medium force and seepage flow mechanics theory,the dynamic response equation of pore pressure of the confined aquifer under laterally cyclic loading is established.Laterally cyclic loading is external dynamic factors on triggering groundwater seepage.Meanwhile,the groundwater seepage will also cause the pore-water pressure change.Based on this,the seepage flow force equation should be a coupled model of seepage force balance model under seepage conditions and stress-strain mechanics model of pore elastic aqueous medium under dynamic stress.At the same time,the influence of the main hydrodynamic parameters on the seepage dynamic equation is discussesd.Considered the characteristic of asymmetry deformation of soil medium by laterally cyclic loading,improved Biot consolidation model and established the dynamic response equation of pore pressure.(3)Based on the hydraulics theory,the well flow dynamic equation and well flow motion equation with the water column in the well as the research object were established,and the influence of well structure parameters on the well flow dynamic equation was analyzed.In this dissertation,the well flow dynamics model is generalized.On the basis of simplifying the head loss and well storage effect during the interactive flow process of water flow from the aquifer to the well water level,the focus is on the movement characteristics of the well flow caused by the force.(4)The mathematical model of the response of the well water level to dynamic stress under two hydrodynamic conditions of seepage(drainage)and non-drainage of the aquifer was established respectively,and by solving the mathematical model,the aquifer excess pore pressure change and the average dynamic stress were obtained The relationship of the change has obtained the quantitative relationship between the water level of the confined well and the dynamic stress.It also reflects the influence of physical and mechanical properties of aquifer medium on hydrodynamic processes.(5)The shaking table text of the single-frequency sine wave load of the well-pore pressured aquifer system was carried out.Based on the experimental results and analysis,it was revealed that the water level of the confined well under the two different hydrodynamic conditions of seepage flow and static water,the response of the water level of the pressure well to vibration all shows oscillation rising,oscillation falling and Oscillation characteristic regular;the change of aquifer pore pressure in the experiment is the result of the combined action of dynamic stress and seepage,which further verifies the rationality of the theoretical equation.At the same time,through quantitative analysis,the primary and secondary relationships of the factors that affect the change of the water level of the confined well under the action of dynamic stress are clarified.