基于块体基础自由振动计算地基阻尼比的新方法
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摘要
提出了一种基于能量守恒原理计算地基土阻尼比的新方法。不同于对数衰减法仅依据振幅计算阻尼比,该方法考虑了体系振动的整个反应时程,克服了对数衰减法对幅值测量精度要求很高的缺陷。数值仿真和实测结果表明:与对数衰减法相比,该方法计算精度较高,抗干扰能力强,稳定性好,即便对于信号干扰比较大的情况,采用该方法也能得到较好的结果。
A new method of subsoil damping ratio identification based on law of conservation of energy is proposed. This method considers the whole time histories of vibration,differs from the traditional damping ratio identification method in the time domain which uses merely the amplitude to calculate damping ratio,and overcomes the defect of the traditional logarithmic decrement method for high accuracy requirement of amplitudes. The subsoil damping ratio of a massive concrete foundation is tested and calculated. The results of numerical simulation and actual test show that this method is of higher precision,stronger anti-noise ability and better stability compared with the traditional logarithmic decrement method. Even if the data acquisition is disturbed seriously by noise,the method proposed is effective and reliable.
A new method of subsoil damping ratio identification based on law of conservation of energy is proposed. This method considers the whole time histories of vibration,differs from the traditional damping ratio identification method in the time domain which uses merely the amplitude to calculate damping ratio,and overcomes the defect of the traditional logarithmic decrement method for high accuracy requirement of amplitudes. The subsoil damping ratio of a massive concrete foundation is tested and calculated. The results of numerical simulation and actual test show that this method is of higher precision,stronger anti-noise ability and better stability compared with the traditional logarithmic decrement method. Even if the data acquisition is disturbed seriously by noise,the method proposed is effective and reliable.
引文
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[6]陈学良,金星,陶夏新,等.考虑试验阻尼效应的一种土体动力双型抛物线本构模型[J].岩土力学,2008,29(8):2102-2110.CHEN Xue-liang,JIN Xing,TAO Xia-xin,et al.A soil dynamic double-parabola constitutive model considering effect of soil test damping[J].Rock and Soil Mechanics,2008,29(8):2102-2110.
[7]陈伟,孔令伟,朱建群.一种土的阻尼比近似计算方法[J].岩土力学,2007,28:789-791.CHEN Wei,KONG Ling-wei,ZHU Jian-qun.A simple method to approximately determine the damping ratio of soils[J].Rock and Soil Mechanics,2007,28:789-791.
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[10]侯兴民,孔令召,陈建立.窗函数对地基阻尼比测试的影响[J].地震工程与工程振动,2009,29(3):150-155.HOU Xing-min,KONG Ling-zhao,CHEN Jian-li.Effect of window function on the subsoil damping ratio[J].Earthquake Engineering and Engineering Vibration,2009,29(3):150-155.
[2]黄宗明,白绍良,赖明.结构地震反应时程分析中的阻尼问题评述[J].地震工程与工程振动,1996,16(2):95-105.HUANG Zong-ming,BAI Shao-liang,LAI Ming.Review on the damping in earthquake response time-history analysis of structures[J].Earthquake Engineering and Engineering Vibration,1996,16(2):95-105.
[3]刘晶波,杜修力.结构动力学[M].北京:机械工业出版社,2005.
[4]尚守平,熊伟,杜运兴,等.饱和场地土动力特性试验研究[J].岩土力学,2008,29(1):23-27.SHANG Shou-ping,XIONG Wei,DU Yun-xing,et al.Experimental study on dynamic characteristics of saturated soils[J].Rock and Soil Mechanics,2008,29(1):23-27.
[5]侯兴民,廖振鹏,黄浩华.动力基础频域响应分析[J].工程力学,2003,20(4):122-127.HOU Xing-min,LIAO Zhen-peng,HUANG Hao-hua.Dynamic response analysis of foundation in the frequency domain[J].Engineering Mechanics,2003,20(4):122-127.
[6]陈学良,金星,陶夏新,等.考虑试验阻尼效应的一种土体动力双型抛物线本构模型[J].岩土力学,2008,29(8):2102-2110.CHEN Xue-liang,JIN Xing,TAO Xia-xin,et al.A soil dynamic double-parabola constitutive model considering effect of soil test damping[J].Rock and Soil Mechanics,2008,29(8):2102-2110.
[7]陈伟,孔令伟,朱建群.一种土的阻尼比近似计算方法[J].岩土力学,2007,28:789-791.CHEN Wei,KONG Ling-wei,ZHU Jian-qun.A simple method to approximately determine the damping ratio of soils[J].Rock and Soil Mechanics,2007,28:789-791.
[8]中华人民共和国机械工业部.GB50040-96动力机器基础设计规范[S].北京:中国计划出版社,2002.
[9]中华人民共和国机械工业部.GB/T50269-97地基动力特性测试规范[S].北京:中国计划出版社,2002.
[10]侯兴民,孔令召,陈建立.窗函数对地基阻尼比测试的影响[J].地震工程与工程振动,2009,29(3):150-155.HOU Xing-min,KONG Ling-zhao,CHEN Jian-li.Effect of window function on the subsoil damping ratio[J].Earthquake Engineering and Engineering Vibration,2009,29(3):150-155.
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