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一种气象干旱综合指数的过程事件研究
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作者 张驰 何慧根 +2 位作者 谢清霞 唐红玉 廖代强 《高原气象》 CSCD 北大核心 2024年第5期1329-1343,共15页
为掌握重庆气象干旱长时间序列演变规律,利用重庆1960-2022年34个国家站的本地化改进型气象干旱综合指数(RMCI)结合区域性气象干旱过程评估地方标准做气象干旱综合指数(MCI)1981-2020年同期对比,进而解析RMCI历史63 a数据结构及其时空... 为掌握重庆气象干旱长时间序列演变规律,利用重庆1960-2022年34个国家站的本地化改进型气象干旱综合指数(RMCI)结合区域性气象干旱过程评估地方标准做气象干旱综合指数(MCI)1981-2020年同期对比,进而解析RMCI历史63 a数据结构及其时空分布特征。研究表明:(1)重庆40 a RMCI单站过程累计频次较MCI偏多4.2%,二者频次-强度拟合都呈显著的指数型分布,两者所有单站过程开始时间的差异率仅为8.1%;重庆东北部为RMCI和MCI单站过程各级旱情的一致高发区,而中心城区、西南部及中部地区发生频率相对较低。(2)重庆63 a RMCI日数据总体呈正态分布,全市及各分区轻旱、中旱、重旱(特旱)日数据分布差异较小(较大),中心城区重旱、特旱日数据较其他分区分别一致性偏大、偏小;RMCI单站、区域过程的频次与强弱都呈显著反相关,其中重庆西部发生轻旱、中旱、特旱单站过程的站均频次最多,而区域过程中特旱的极差绝对值最大、中旱次之。(3)63 a间重庆RMCI单站和区域气象干旱过程强度趋势都不显著,但1962-2013年却均为显著减小趋势,2013年后重庆过程强度的总体减弱与21世纪以来高温日数的年代际减少有所关联,气象干旱过程事件具有复杂的年际和年代际信号。RMCI单站过程事件主要存在2~6 a和准20 a的周期振荡,发生在重庆东北部偏东和东南部偏北地区的单站过程事件“变干”尤为显著;RMCI区域过程事件则存在2~3 a、4~6 a和8~12 a的周期振荡,开始于伏旱期及7月的区域过程事件频次最多、强度最强,而秋旱期和12月的频次相对最少、强度最弱。 展开更多
关键词 气象干旱 rmci 单站过程 区域过程 频次 强度
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Discussion on“Empirical methods for determining shaft bearing capacity of semi-deep foundations socketed in rocks”[J Rock Mech Geotech Eng 6(2017)1140-151] 被引量:3
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作者 Ergin Arioglu Pinar Toru Seker Hasan Burak Gokce 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第3期603-606,共4页
A new comprehensive set of data(n = 178) is compiled by adding a data set(n = 72) collected by Arioglu et al.(2007) to the data set(n = 106) presented in Rezazadeh and Eslami(2017). Then, the compiled data s... A new comprehensive set of data(n = 178) is compiled by adding a data set(n = 72) collected by Arioglu et al.(2007) to the data set(n = 106) presented in Rezazadeh and Eslami(2017). Then, the compiled data set is evaluated regardless of the variation in lithology/strength. The proposed empirical equation in this study comprises a wider range of uniaxial compressive strength(UCS)(0.15 MPa 〈 σ_(rc) 〈156 MPa) and various rock types. Rock mass cuttability index(RMCI) is correlated with shaft resistance(r_s) to predict the shaft resistance of rock-socketed piles. The prediction capacity of the RMCI versus r_s equation is also found to be in a fair good agreement with the presented data in Rezazadeh and Eslami(2017). Since the RMCI is a promising parameter in the prediction of shaft resistance, the researchers in the rock-socketed pile design area should consider this parameter in the further investigations. 展开更多
关键词 Uniaxial compressive strength (UCS) Rock mass cuttability index rmci Shaft resistance Rock socketed piles Database
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Reply to Discussion on “Empirical methods for determining shaft bearing capacity of semi-deep foundations socketed in rocks”
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作者 S.Rezazadeh A.Eslami 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第3期607-609,共3页
Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high... Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high bearing capacity. In this study, the unconfined compressive strength(UCS) and rock mass cuttability index(RMCI) have been applied to investigating the shaft bearing capacity. For this purpose, a comprehensive database of 178 full-scale load tests is compiled by adding a data set(n = 72)collected by Arioglu et al.(2007) to the data set(n = 106) presented in Rezazadeh and Eslami(2017).Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS/RMCI. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data(series 3 in Rezazadeh and Eslami(2017)). Since rock-socketed shafts are supported by rock mass(not intact rock),a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, based upon RMR and RQD to consider the effect of the rock mass properties. 展开更多
关键词 Shaft bearing capacity Semi-deep foundations Database Unconfined compressive strength (UCS) Rock mass cuttability index rmci
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