自由渗流面及渗流量推求的数值计算方法探讨
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摘要
自由渗流面具有复杂的非线性,较难确定。本文采用开源地下水数值模拟程序MODFLOW及SUTRA,分别运用MODFLOW模型中干湿单元转化技术、SUTRA模型中单元渗透矩阵调整法以及本文建立的缓变渗透系数矩阵法推求自由渗流面。对比其求解结果表明,采用MODFLOW运用干湿转化技术求解自由渗透面的方法稳定性最好、精度最高,而采用缓变渗透系数矩阵法的SUTRA程序,改善了传统单元渗透矩阵调整法的不稳定性,提高了数值计算精度,避免了MODFLOW必须矩形网格的局限性,是一种实用的计算自由渗流面及估算地下水与河流水量交换量的方法。
Free seepage surface is difficult to be determined because of nonlinear processes. Based on open-sources of groundwater modeling programs of MODFLOW and SUTRA,the seepage face was simulated using the dry-wet cell transfer technique in MODFLOW,adjustment of hydraulic conductivity and smooth variation of hydraulic conductivity in SUTRA. Simulated results of these three methods shows that the dry-wet cell transfer technique in MODFLOW offers a steady and highest precision of the equation solution which describes free seepage surface; the method of smooth variation of hydraulic conductivity we developed in this study improves steady of the equation solution because this solution using the original method of adjustment of hydraulic conductivity in SULTRA is often unsteady. The proposed method also avoids limitations in MODFLOW that grid must be rectangular. it offers a practical method for calculating the free seepage face and estimating water exchange between groundwater and river.
Free seepage surface is difficult to be determined because of nonlinear processes. Based on open-sources of groundwater modeling programs of MODFLOW and SUTRA,the seepage face was simulated using the dry-wet cell transfer technique in MODFLOW,adjustment of hydraulic conductivity and smooth variation of hydraulic conductivity in SUTRA. Simulated results of these three methods shows that the dry-wet cell transfer technique in MODFLOW offers a steady and highest precision of the equation solution which describes free seepage surface; the method of smooth variation of hydraulic conductivity we developed in this study improves steady of the equation solution because this solution using the original method of adjustment of hydraulic conductivity in SULTRA is often unsteady. The proposed method also avoids limitations in MODFLOW that grid must be rectangular. it offers a practical method for calculating the free seepage face and estimating water exchange between groundwater and river.
引文
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[6]张乾飞,吴中如.有自由面非稳定渗流分析的改进截止负压法[J].岩土工程学报.2005.27(1):48-54.
[7]MARKSTRON S L,NISWONGER R G,REGAN R S,et al.GSFLOW:coupled ground-water and surface-water flow model based on the integration of the precipitation-runoff modeling system(PRMS)and the modular ground-water flow model(MODFLOW-2005)[R].Reston.VA:USGS.2008.
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[10]马建良,陈喜,程勤波,等.一维变密度溶质运移实验及参数推求[J].水资源保护.2008.24(3):8-11.
[11]党发宁,王晓章,耿旭光,等.求解渗流自由面的一种新方法[J].水力发电学报.2004.23(6):88-91.
[12]付延玲,周志芳,武永霞.改进复合单元渗透矩阵调整法求解自由面三维渗流场[J].岩土工程学报.2009.31(9):1434-1439.
[13]裴利华.有自由面三维非稳定渗流数值模拟若干关键技术研究[D].南京:河海大学.2005.
[14]程勤波,陈喜,凌敏华,等.单环入渗试验与数值反演法结合推求土壤水力参数[J].水文地质工程地质.2010.37(1):118-123.
[15]陈江.基于ansys的渗流自由面计算方法[J].岩土工程技术.2008.22(5):236-240.
[2]张有天,陈平,等.有自由面渗流分析的初流量法[J].水利学报.1988.8:18-26.
[3]速宝玉,朱岳明.不变网格确定渗流自由面的节点虚流量法[J].河海大学学报.1991.19(5):113-117.
[4]Bathe K J.Finite element free surface seepage analysis without mesh iteration[J].Int Num Anal Methods in Geomechanics.1979.3:3-22.
[5]马淑芝,贾洪彪,唐辉明,等.复合单元法在求解有自由面渗流问题中的应用[J].水文地质工程地质增刊.2004(增):122-124.
[6]张乾飞,吴中如.有自由面非稳定渗流分析的改进截止负压法[J].岩土工程学报.2005.27(1):48-54.
[7]MARKSTRON S L,NISWONGER R G,REGAN R S,et al.GSFLOW:coupled ground-water and surface-water flow model based on the integration of the precipitation-runoff modeling system(PRMS)and the modular ground-water flow model(MODFLOW-2005)[R].Reston.VA:USGS.2008.
[8]Voss C I,Provost A M.A Model for Saturated-Unsaturated,Variable-Density Ground-Water Flow with Solute or Energy Transport(SUTRA)[M].Reston.VA:USGS.2008.
[9]董佩,王旭升.MODFLOW模拟自由面渗流的应用与讨论[J].工程勘察.2009.7:7-30.
[10]马建良,陈喜,程勤波,等.一维变密度溶质运移实验及参数推求[J].水资源保护.2008.24(3):8-11.
[11]党发宁,王晓章,耿旭光,等.求解渗流自由面的一种新方法[J].水力发电学报.2004.23(6):88-91.
[12]付延玲,周志芳,武永霞.改进复合单元渗透矩阵调整法求解自由面三维渗流场[J].岩土工程学报.2009.31(9):1434-1439.
[13]裴利华.有自由面三维非稳定渗流数值模拟若干关键技术研究[D].南京:河海大学.2005.
[14]程勤波,陈喜,凌敏华,等.单环入渗试验与数值反演法结合推求土壤水力参数[J].水文地质工程地质.2010.37(1):118-123.
[15]陈江.基于ansys的渗流自由面计算方法[J].岩土工程技术.2008.22(5):236-240.