二次序列响应面法分析重力坝的动力可靠度
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摘要
提出了用二次序列响应面法分析重力坝可靠度的方法。该方法用界面元法对重力坝进行确定性计算 ,在适当的区间内用统计的方法确定各变量的样本点 ,经过若干次重复计算 ,由界面元法的计算结果可以得到该结构的响应面函数 ,然后由这一函数算出重力坝可靠度的近似值。用同样的方法可得第二、第三个响应面函数 ,并使可靠度计算结果逐步达到良好的精度要求。这一方法与统计可靠度分析方法相比可以减少大量的计算工作量。对于包含混凝土特性和坝上游水位等随机变量的重力坝 ,本文用上述方法计算了一些关键时刻重力坝抗裂的动力可靠度 ,并据此分析了在整个地震过程中该坝抗裂可靠指标 β(t)随时间 t的变化规律。
A method to analyze reliability of gravity dams using the second order sequence response surface method is described. A gravity dam is modelled and analyzed with an interface element code as in deterministic studies. After Choosing the points of basic random variables in a proper region, the computation is repeated several times so that the response given by the interface element code can be reasonably fitted by the graduating function which can be used to estimate the reliability of gravity dam. Using the procedure described above, sequential response functions are obtained, and the reliability indices gradually converge to the exact value. Comparing with the conventional methods of statistical relability analysis, the time consuming computational effort is reduced by the second order sequence response surface method. For the gravity dam involving uncertain concrete properties and random height of water level, some dynamic reliability indices against fissuring are computed and a curve which describes the reliability index β(t) varying with time t within the period of earthquake is obtained.
A method to analyze reliability of gravity dams using the second order sequence response surface method is described. A gravity dam is modelled and analyzed with an interface element code as in deterministic studies. After Choosing the points of basic random variables in a proper region, the computation is repeated several times so that the response given by the interface element code can be reasonably fitted by the graduating function which can be used to estimate the reliability of gravity dam. Using the procedure described above, sequential response functions are obtained, and the reliability indices gradually converge to the exact value. Comparing with the conventional methods of statistical relability analysis, the time consuming computational effort is reduced by the second order sequence response surface method. For the gravity dam involving uncertain concrete properties and random height of water level, some dynamic reliability indices against fissuring are computed and a curve which describes the reliability index β(t) varying with time t within the period of earthquake is obtained.
引文
1 KimS H,NaW S.Response surface m ethod usingvector projected sampling points.Struct.Safety,1997;19(1):3—19
2 RajashekharM R,EllingwoodB R.A new look at theresponse surface approach for reliability analysis.StrucuralSafety,1993;12:205—220
3 L iuY W,FredMoses.A sequential response surfacem ethod and its application in the reliability analysis ofaircraft structural system s.StructuralSafety,1994,16:39—46
4 BucherC G,BourgundU .A fast and efficient responsesurface approach for structural reliability problem s.StructuralSafety,1990;7:57—66
5 Maym onG.Direct com putation of the design point of astochastic structure using a finite element code.StructuralSafety,1994;14:185—202
6 WongF S.Slope reliability and response surface m e-thod.Journal ofGeotechnicalEngineering,ASCE.1985,111:32—53
7 卓家寿,赵 宁.不连续介质静、动力分析的刚体—弹簧元法.河海大学学报,1993;21(5):34—42
8 赵 宁,卓家寿.动力分析的刚体—界面元与有限元耦合法.河海大学学报,1994;22(6):8—14
9 武清玺,卓家寿.结构可靠度分析的变 f序列响应面法及其应用.河海大学学报,2001;29(2):75—78
2 RajashekharM R,EllingwoodB R.A new look at theresponse surface approach for reliability analysis.StrucuralSafety,1993;12:205—220
3 L iuY W,FredMoses.A sequential response surfacem ethod and its application in the reliability analysis ofaircraft structural system s.StructuralSafety,1994,16:39—46
4 BucherC G,BourgundU .A fast and efficient responsesurface approach for structural reliability problem s.StructuralSafety,1990;7:57—66
5 Maym onG.Direct com putation of the design point of astochastic structure using a finite element code.StructuralSafety,1994;14:185—202
6 WongF S.Slope reliability and response surface m e-thod.Journal ofGeotechnicalEngineering,ASCE.1985,111:32—53
7 卓家寿,赵 宁.不连续介质静、动力分析的刚体—弹簧元法.河海大学学报,1993;21(5):34—42
8 赵 宁,卓家寿.动力分析的刚体—界面元与有限元耦合法.河海大学学报,1994;22(6):8—14
9 武清玺,卓家寿.结构可靠度分析的变 f序列响应面法及其应用.河海大学学报,2001;29(2):75—78
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