The stability of rock slope is often controlled by the existing discontinuous surfaces, such as discrete fractures, which are ubiquitously distributing in a geological medium. In contrast with the traditional approach...The stability of rock slope is often controlled by the existing discontinuous surfaces, such as discrete fractures, which are ubiquitously distributing in a geological medium. In contrast with the traditional approaches used in soil slope with a continuous assumption, the simulation methods of jointed rock slope are different from that of in soil slope. This paper presents a study on jointed rock slope stability using the proposed discontinuous approach, which considers the effects of discrete fractures. Comparing with traditional methods to model fractures in an implicit way, the presented approach provides a method to simulate fractures in an explicit way, where grids between rock matrix and fractures are independent. To complete geometric components generation and mesh partition for the model, the corresponding algorithms were devised. To evaluate the stability state of rock slope quantitatively, the strength reduction method was integrated into our analysis framework. A benchmark example was used to verify the validation of the approach. A jointed rock slope, which contains natural fractures, was selected as a case study and was simulated regarding the workflow of our framework. It was set up in the light of the geological condition of the site. Slope stability was evaluated under different loading conditions with various fracture patterns. Numerical results show that fractures have significant contributions to slope stability, and different fracture patterns would lead to different shapes of the slip surface. The devised method has the ability to calculate a non-circular slip surface, which is different from a circular slip surface obtained by classical methods.展开更多
With the east section of the Changji sag Zhunger Basin as a case study, both a principal curvature method and a moving least square method are elaborated. The moving least square method is introduced, for the first ti...With the east section of the Changji sag Zhunger Basin as a case study, both a principal curvature method and a moving least square method are elaborated. The moving least square method is introduced, for the first time, to fit a stratum surface. The results show that, using the same-degree base function, compared with a traditional least square method, the moving least square method can produce lower fitting errors, the fitting surface can describe the morphological characteristics of stratum surfaces more accurately and the principal curvature values vary within a wide range and may be more suitable for the prediction of the distribution of structural fractures. The moving least square method could be useful in curved surface fitting and stratum curvature analysis.展开更多
Surface fractures have a great impact on ice shelf stability in Antarctica and can be considered precursors of ice shelf calving.However,our understanding of the spatial distribution and temporal evolution of surface ...Surface fractures have a great impact on ice shelf stability in Antarctica and can be considered precursors of ice shelf calving.However,our understanding of the spatial distribution and temporal evolution of surface fractures on the Antarctic ice shelf is limited.In this study,a ResUNet model was implemented on the Moderate Resolution Imaging Spectroradiometer(MODIS)-based Mosaic of Antarctica(MOA)to identify the spatial distribution of Antarctic ice shelf surface fractures in 2004,2009,and 2014.The accuracy of identification had an F1 value of 0.771.Our model identified 44744.59±2619.61 km^(2)of surface fractures in 2004,43737.15±2644.60 km^(2)in 2009,and 42978.67±2639.33 km^(2)in 2014.The reduction is primarily attributed to the variation in surface fractures within 20 km of the ice front,paratactically in the Amundsen and Wilkes sectors.Ice shelves in the Amundsen sector typically have a widespread distribution of surface fractures,with particularly high concentrations found in the Thwaites Ice Shelf,Crosson Ice Shelf and Getz Ice Shelf.The Brunt Ice Shelf also exhibits numerous surface fractures.This study provides comprehensive and detailed information about surface fractures on Antarctic ice shelves,carrying implications for evaluating ice shelf vulnerability.展开更多
目的：探讨踝关节面有限切开复位微创接骨术（MIPO）结合锁定钢板内固定治疗对胫骨 Pilon骨折预后的影响。方法将84例经 CT 或 X 线检查确诊为胫骨 Pilon 骨折患者采用随机数字表法分为 A 组及 B 组各42例，A 组采用 MIPO 结合锁定钢板...目的：探讨踝关节面有限切开复位微创接骨术（MIPO）结合锁定钢板内固定治疗对胫骨 Pilon骨折预后的影响。方法将84例经 CT 或 X 线检查确诊为胫骨 Pilon 骨折患者采用随机数字表法分为 A 组及 B 组各42例，A 组采用 MIPO 结合锁定钢板内固定治疗，B 组采用切开复位内固定治疗，术后对两组患者进行临床及影像学随访，对比分析两组疗效、并发症。结果A 组术中出血量少于 B 组（t ＝8．963，P ＜0．05），术后疼痛评分低于 B 组（t ＝10．789，P ＜0．05），而满意度评分高于 B 组（t ＝8．963，P ＜0．05），术后住院时间、骨折愈合时间短于 B 组（t ＝9．362，10．556，P ＜0．05）。根据 Conroy 评分系统及 Tenny 评分系统，A 组优、良率分别为95．24％、76．19％，均高于 B 组的92．86％、71．43％，差异均有统计学意义（χ2＝6．222、6．574，均 P ＜0.05）。A 组总并发症发生率（2．38％）显著低于 B 组（21．43％）（χ2＝7．265，P ＜0．05）。结论MIPO 结合锁定钢板内固定治疗 Pilon 骨折可减少软组织剥离，减少手术对患者的创伤，降低患者术后并发症，有利于患者尽早康复。展开更多
目的分析血小板活动指标血小板表面P-选择素(CD62P)、溶酶体颗粒糖蛋白(CD63)、脂代谢异常与股骨颈骨折术后股骨头缺血性坏死(avascular necrosis of the femoral head,ANFH)的相关性,并探讨术后ANFH的危险因素。方法对2015年2月至2019...目的分析血小板活动指标血小板表面P-选择素(CD62P)、溶酶体颗粒糖蛋白(CD63)、脂代谢异常与股骨颈骨折术后股骨头缺血性坏死(avascular necrosis of the femoral head,ANFH)的相关性,并探讨术后ANFH的危险因素。方法对2015年2月至2019年4月我院收治的302例股骨颈骨折患者的临床资料进行回顾性分析,其中男155例、女147例。年龄51~89岁,平均(65.82±8.15)岁,骨折至手术时间42h^10天,平均(5.20±1.00)天。致伤原因:交通事故52例、意外摔倒211例、其它39例;Garden分型:Ⅰ型41例、Ⅱ型204例、Ⅲ型45例、Ⅳ型12例;复位方式:切开复位202例、闭合复位100例;固定方式:空心螺钉加压内固定203例、钢板内固定99例。统计ANFH的发生率,并分析术后CD62P、CD63、脂代谢异常与ANFH的关系及其危险因素。结果 ANFH发生率为12.58%;ANFH发生者术后CD62P、CD63水平均低于未发生者(P=0.000、0.000),而TC、LDLC水平均高于未发生者(P=0.000、0.000);年龄>80岁、骨折移位、GardenⅢ/Ⅳ型、骨折至手术时间>7天、术前牵引、术后CD62P、CD63偏低、术后TC、LDLC偏高、内固定物未取出均为ANFH发生的独立危险因素。结论股骨颈骨折术后有ANFH发生风险,且ANFH发生者术后CD62P、CD63水平偏低,TC、LDLC水平偏高,患者年龄>80岁、骨折移位等均可增加ANFH的发生风险。展开更多
基金supported by National Key Research and Development Plan of China (No. 2018YFF01014204)"Fundamental Research Program of China (No. 2015CB057906)"
文摘The stability of rock slope is often controlled by the existing discontinuous surfaces, such as discrete fractures, which are ubiquitously distributing in a geological medium. In contrast with the traditional approaches used in soil slope with a continuous assumption, the simulation methods of jointed rock slope are different from that of in soil slope. This paper presents a study on jointed rock slope stability using the proposed discontinuous approach, which considers the effects of discrete fractures. Comparing with traditional methods to model fractures in an implicit way, the presented approach provides a method to simulate fractures in an explicit way, where grids between rock matrix and fractures are independent. To complete geometric components generation and mesh partition for the model, the corresponding algorithms were devised. To evaluate the stability state of rock slope quantitatively, the strength reduction method was integrated into our analysis framework. A benchmark example was used to verify the validation of the approach. A jointed rock slope, which contains natural fractures, was selected as a case study and was simulated regarding the workflow of our framework. It was set up in the light of the geological condition of the site. Slope stability was evaluated under different loading conditions with various fracture patterns. Numerical results show that fractures have significant contributions to slope stability, and different fracture patterns would lead to different shapes of the slip surface. The devised method has the ability to calculate a non-circular slip surface, which is different from a circular slip surface obtained by classical methods.
基金Projects 2007CB209405 and 2002CB412702 supported by the National Basic Research Program of ChinaKZCX2-YW-113 by the Important Directive Item of the Knowledge Innovation Project of Chinese Academy of Sciences 40772100 by the National Natural Science Foundation of China
文摘With the east section of the Changji sag Zhunger Basin as a case study, both a principal curvature method and a moving least square method are elaborated. The moving least square method is introduced, for the first time, to fit a stratum surface. The results show that, using the same-degree base function, compared with a traditional least square method, the moving least square method can produce lower fitting errors, the fitting surface can describe the morphological characteristics of stratum surfaces more accurately and the principal curvature values vary within a wide range and may be more suitable for the prediction of the distribution of structural fractures. The moving least square method could be useful in curved surface fitting and stratum curvature analysis.
基金supported by the National Natural Science Foundation of China(grant no.41830536,41925027)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(grant no.311022003)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23ptpy99,231GBJ022).
文摘Surface fractures have a great impact on ice shelf stability in Antarctica and can be considered precursors of ice shelf calving.However,our understanding of the spatial distribution and temporal evolution of surface fractures on the Antarctic ice shelf is limited.In this study,a ResUNet model was implemented on the Moderate Resolution Imaging Spectroradiometer(MODIS)-based Mosaic of Antarctica(MOA)to identify the spatial distribution of Antarctic ice shelf surface fractures in 2004,2009,and 2014.The accuracy of identification had an F1 value of 0.771.Our model identified 44744.59±2619.61 km^(2)of surface fractures in 2004,43737.15±2644.60 km^(2)in 2009,and 42978.67±2639.33 km^(2)in 2014.The reduction is primarily attributed to the variation in surface fractures within 20 km of the ice front,paratactically in the Amundsen and Wilkes sectors.Ice shelves in the Amundsen sector typically have a widespread distribution of surface fractures,with particularly high concentrations found in the Thwaites Ice Shelf,Crosson Ice Shelf and Getz Ice Shelf.The Brunt Ice Shelf also exhibits numerous surface fractures.This study provides comprehensive and detailed information about surface fractures on Antarctic ice shelves,carrying implications for evaluating ice shelf vulnerability.
文摘目的：探讨踝关节面有限切开复位微创接骨术（MIPO）结合锁定钢板内固定治疗对胫骨 Pilon骨折预后的影响。方法将84例经 CT 或 X 线检查确诊为胫骨 Pilon 骨折患者采用随机数字表法分为 A 组及 B 组各42例，A 组采用 MIPO 结合锁定钢板内固定治疗，B 组采用切开复位内固定治疗，术后对两组患者进行临床及影像学随访，对比分析两组疗效、并发症。结果A 组术中出血量少于 B 组（t ＝8．963，P ＜0．05），术后疼痛评分低于 B 组（t ＝10．789，P ＜0．05），而满意度评分高于 B 组（t ＝8．963，P ＜0．05），术后住院时间、骨折愈合时间短于 B 组（t ＝9．362，10．556，P ＜0．05）。根据 Conroy 评分系统及 Tenny 评分系统，A 组优、良率分别为95．24％、76．19％，均高于 B 组的92．86％、71．43％，差异均有统计学意义（χ2＝6．222、6．574，均 P ＜0.05）。A 组总并发症发生率（2．38％）显著低于 B 组（21．43％）（χ2＝7．265，P ＜0．05）。结论MIPO 结合锁定钢板内固定治疗 Pilon 骨折可减少软组织剥离，减少手术对患者的创伤，降低患者术后并发症，有利于患者尽早康复。
文摘目的分析血小板活动指标血小板表面P-选择素(CD62P)、溶酶体颗粒糖蛋白(CD63)、脂代谢异常与股骨颈骨折术后股骨头缺血性坏死(avascular necrosis of the femoral head,ANFH)的相关性,并探讨术后ANFH的危险因素。方法对2015年2月至2019年4月我院收治的302例股骨颈骨折患者的临床资料进行回顾性分析,其中男155例、女147例。年龄51~89岁,平均(65.82±8.15)岁,骨折至手术时间42h^10天,平均(5.20±1.00)天。致伤原因:交通事故52例、意外摔倒211例、其它39例;Garden分型:Ⅰ型41例、Ⅱ型204例、Ⅲ型45例、Ⅳ型12例;复位方式:切开复位202例、闭合复位100例;固定方式:空心螺钉加压内固定203例、钢板内固定99例。统计ANFH的发生率,并分析术后CD62P、CD63、脂代谢异常与ANFH的关系及其危险因素。结果 ANFH发生率为12.58%;ANFH发生者术后CD62P、CD63水平均低于未发生者(P=0.000、0.000),而TC、LDLC水平均高于未发生者(P=0.000、0.000);年龄>80岁、骨折移位、GardenⅢ/Ⅳ型、骨折至手术时间>7天、术前牵引、术后CD62P、CD63偏低、术后TC、LDLC偏高、内固定物未取出均为ANFH发生的独立危险因素。结论股骨颈骨折术后有ANFH发生风险,且ANFH发生者术后CD62P、CD63水平偏低,TC、LDLC水平偏高,患者年龄>80岁、骨折移位等均可增加ANFH的发生风险。
