In the numerical simulation of groundwater flow, uncertainties often affect the precision of the simulation results. Stochastic and statistical approaches such as the Monte Carlo method, the Neumann expansion method and the Taylor series expansion, are commonly employed to estimate uncertainty in the final output. Based on the first-order interval perturbation method, a combination of the interval and perturbation methods is proposed as a viable alternative and compared to the well-known equal interval continuous sampling method (EICSM). The approach was realized using the GFModel (an unsaturated-saturated groundwater flow simulation model) program. This study exemplifies scenarios of three distinct interval parameters, namely, the hydraulic conductivities of six equal parts of the aquifer, their boundary head conditions, and several hydrogeological parameters (e.g. specific storativity and extraction rate of wells). The results show that the relative errors of deviation of the groundwater head extremums (RDGE) in the late stage of simulation are controlled within approximately ±5% when the changing rate of the hydrogeological parameter is no more than 0.2. From the viewpoint of the groundwater head extremums, the relative errors can be controlled within ±1.5%. The relative errors of the groundwater head variation are within approximately ±5% when the changing rate is no more than 0.2. The proposed method of this study is applicable to unsteady-state confined water flow systems.
Calc-alkaline granites (excluding A-and M-type) could be divided into two petrogenic series,I,e,the syntexis series and the transformation series according to their genetic mechanisms.In the light of this classification we found that granites of these two series often aligne in paired zones parallel to contemporaneous B-type or intracontinental compression-subduction zones within ascended slabs,re-sulting in a regular zonal pattern together with subduction zones.Thus,they are defined as twin granite belts.According to the spatial relations between the granite belts and the subduction zones,the twin granite belts could be classified as A, AB and B-type .The zonation of granites of the two series in the northern part of the East Qinlin area could be cited as a typical example of A-type twin granite belts related to the Yenshanian intracontinenta compression-subduction movement in the area.In this paper the tectonic settings and petrogenic features of the twin granites belts in East Qinlin are systematically described,and a tectonic model for granitic magma genesis in intracontinental compression-subduction environments has been proposed.In this model the forma-tion of A-type twin granite belts is closely connected with tectonic movements in terms of the prince-ple,rule and dynamics of material differentiation in the lithosphere. 相似文献
