At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is es...At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.展开更多
[目的]对区域性泥石流敏感性进行分析,为吉林省洮南市泥石流灾害预测研究提出一种高效快捷的分析模型。[方法]针对现行大多数概率统计模型预测率较低的不足,利用人工智能算法中效果明显的随机森林算法,以吉林省洮南市西北部山区为研究区...[目的]对区域性泥石流敏感性进行分析,为吉林省洮南市泥石流灾害预测研究提出一种高效快捷的分析模型。[方法]针对现行大多数概率统计模型预测率较低的不足,利用人工智能算法中效果明显的随机森林算法,以吉林省洮南市西北部山区为研究区域,选用高程、坡度、坡向、平面曲率、剖面曲率、河流、归一化差分植被指数、地形湿度指数、土地利用及岩性10个评价因子构建了频率比和随机森林泥石流敏感性评价模型进行对比验证。模型准确性的验证方法采用受试者特征曲线(ROC曲线)及累积频率曲线下面积(area under curve,AUC)。[结果]随机森林对研究区泥石流敏感性进行分析,并通过GIS将敏感性图分为5个敏感性区域,位于高敏感性区以上的灾害点占82.3%。验证模型成功率及预测率分别为88.4%与90.4%,相较于频率比的成功率及预测率(86.4%和75.1%)效果良好。[结论]在洮南市北部进行泥石流敏感性分析中,采用随机森林方法进行建模,并利用频率比方法进行对比,结果显示随机森林法结果可靠准确。展开更多
针对信息量模型(information value model,IVM)在地质灾害易发性评价中未考虑各评价指标之间的权重大小和冗余属性的约简问题,本文引入粗糙集(rough set,RS)理论,提出一种基于粗糙集理论的信息量评价模型(RS-IVM)方法.通过RS理论属性重...针对信息量模型(information value model,IVM)在地质灾害易发性评价中未考虑各评价指标之间的权重大小和冗余属性的约简问题,本文引入粗糙集(rough set,RS)理论,提出一种基于粗糙集理论的信息量评价模型(RS-IVM)方法.通过RS理论属性重要度分析,约简重要度极低的冗余属性,并根据属性重要度得到有效评价指标的权重系数.在此基础上,通过加权信息量求和,使评价结果得到优化.以吉林省泥石流灾害为研究对象,选取高程、坡度、坡向、地层岩性、人口密度、地貌类型、流域、植被覆盖率和年降水量9项影响因子作为评价指标.分别用RS-IVM方法和IVM方法对吉林省泥石流灾害进行易发性评价计算,并用预测率曲线进行对比.结果表明,RS-IVM方法优于IVM方法.最后,采用自然间断点划分法将RS-IVM方法得到的易发性评价结果划分为极高易发区、高易发区、中易发区、低易发区和极低易发区5个易发性等级,其面积分别占吉林省总面积的34.87%,24.37%,10.92%,20.82%,9.02%.其中,高易发区和极高易发区主要分布于东南山区和西北局部地区,低易发区和极低易发区主要分布于中西部平原地带.展开更多
基金National Natural Science Fund of China under Nos.52168072 and 51808467High-level Talents Support Plan of Yunnan Province of China(2020)。
文摘At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.
文摘[目的]对区域性泥石流敏感性进行分析,为吉林省洮南市泥石流灾害预测研究提出一种高效快捷的分析模型。[方法]针对现行大多数概率统计模型预测率较低的不足,利用人工智能算法中效果明显的随机森林算法,以吉林省洮南市西北部山区为研究区域,选用高程、坡度、坡向、平面曲率、剖面曲率、河流、归一化差分植被指数、地形湿度指数、土地利用及岩性10个评价因子构建了频率比和随机森林泥石流敏感性评价模型进行对比验证。模型准确性的验证方法采用受试者特征曲线(ROC曲线)及累积频率曲线下面积(area under curve,AUC)。[结果]随机森林对研究区泥石流敏感性进行分析,并通过GIS将敏感性图分为5个敏感性区域,位于高敏感性区以上的灾害点占82.3%。验证模型成功率及预测率分别为88.4%与90.4%,相较于频率比的成功率及预测率(86.4%和75.1%)效果良好。[结论]在洮南市北部进行泥石流敏感性分析中,采用随机森林方法进行建模,并利用频率比方法进行对比,结果显示随机森林法结果可靠准确。
文摘针对信息量模型(information value model,IVM)在地质灾害易发性评价中未考虑各评价指标之间的权重大小和冗余属性的约简问题,本文引入粗糙集(rough set,RS)理论,提出一种基于粗糙集理论的信息量评价模型(RS-IVM)方法.通过RS理论属性重要度分析,约简重要度极低的冗余属性,并根据属性重要度得到有效评价指标的权重系数.在此基础上,通过加权信息量求和,使评价结果得到优化.以吉林省泥石流灾害为研究对象,选取高程、坡度、坡向、地层岩性、人口密度、地貌类型、流域、植被覆盖率和年降水量9项影响因子作为评价指标.分别用RS-IVM方法和IVM方法对吉林省泥石流灾害进行易发性评价计算,并用预测率曲线进行对比.结果表明,RS-IVM方法优于IVM方法.最后,采用自然间断点划分法将RS-IVM方法得到的易发性评价结果划分为极高易发区、高易发区、中易发区、低易发区和极低易发区5个易发性等级,其面积分别占吉林省总面积的34.87%,24.37%,10.92%,20.82%,9.02%.其中,高易发区和极高易发区主要分布于东南山区和西北局部地区,低易发区和极低易发区主要分布于中西部平原地带.
