中国科学院国家天文台500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)台址位于岩溶洼地内,开挖完成后的洼地边坡外形接近球冠型边坡,属于轴对称圆形凹坡,坡体由胶结的土石混合体和石灰岩组成,...中国科学院国家天文台500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)台址位于岩溶洼地内,开挖完成后的洼地边坡外形接近球冠型边坡,属于轴对称圆形凹坡,坡体由胶结的土石混合体和石灰岩组成,局部稳定性良好,整体稳定性有待评价。目前边坡整体稳定性评价通常采用基于平面应变假定的极限平衡法,由于未考虑边坡外形,该方法用于轴对称圆形凹坡稳定性的评价结果有偏差。为消除上述偏差,将轴对称圆形凹坡滑体划分为多个环形条块,考虑环形条块轴力的抗滑作用,提出了针对轴对称圆形凹坡的极限平衡法改进方法;并采用数值分析方法对改进后的简化Bishop法进行验证,结果表明改进后的简化Bishop法安全系数计算结果较未改进方法略有提高,与数值分析法结果基本一致。同时给出轴对称圆形凸坡的安全系数计算公式,计算结果表明圆形凸坡稳定性与直线形边坡较为接近。上述两种计算方法为类似外形的边坡稳定性评价提供了新的途径。展开更多
We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface (307.69 km) and constructed a...We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface (307.69 km) and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 (SCH2010) based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square (RMS) error of AX, AY, and AZ and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level (CGRF2010) is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation off at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well.展开更多
文摘中国科学院国家天文台500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)台址位于岩溶洼地内,开挖完成后的洼地边坡外形接近球冠型边坡,属于轴对称圆形凹坡,坡体由胶结的土石混合体和石灰岩组成,局部稳定性良好,整体稳定性有待评价。目前边坡整体稳定性评价通常采用基于平面应变假定的极限平衡法,由于未考虑边坡外形,该方法用于轴对称圆形凹坡稳定性的评价结果有偏差。为消除上述偏差,将轴对称圆形凹坡滑体划分为多个环形条块,考虑环形条块轴力的抗滑作用,提出了针对轴对称圆形凹坡的极限平衡法改进方法;并采用数值分析方法对改进后的简化Bishop法进行验证,结果表明改进后的简化Bishop法安全系数计算结果较未改进方法略有提高,与数值分析法结果基本一致。同时给出轴对称圆形凸坡的安全系数计算公式,计算结果表明圆形凸坡稳定性与直线形边坡较为接近。上述两种计算方法为类似外形的边坡稳定性评价提供了新的途径。
基金supported by the National Natural Science Foundation of China(No.41404053)Special Project for MeteoScientifi c Research in the Public Interest(No.GYHY201306073)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20140994)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(No.14KJB170012)the Training Program of Innovation and Entrepreneurship for Undergraduates of NUIST(No.201510300178)
文摘We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface (307.69 km) and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 (SCH2010) based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square (RMS) error of AX, AY, and AZ and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level (CGRF2010) is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation off at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well.