According to the engineering features of subgrade cave roof in karst region, the clamped beam model of subgrade cave roof in karst region was set up. Based on the catastrophe theory, the cusp catastrophe model for bea...According to the engineering features of subgrade cave roof in karst region, the clamped beam model of subgrade cave roof in karst region was set up. Based on the catastrophe theory, the cusp catastrophe model for bearing capacity of subgrade cave roof and safe thickness of subgrade cave roof in karst region was established. The necessary instability conditions of subgrade cave roof were deduced, and then the methods to determine safe thickness of cave roofs under piles and bearing capacity of subgrade cave roof were proposed. At the same time, a practical engineering project was applied to verifying this method, which has been proved successfu1ly. At last, the major factors that affect the stability on cave roof under pile in karst region were deeply discussed and some results in quality were acquired.展开更多
A new species of the genusOdorrana is described from a completely dark karst cave of northeastern Guangxi, southern China. The new species,Odorranalipuensissp. nov., can be distinguished from its congeners by a combin...A new species of the genusOdorrana is described from a completely dark karst cave of northeastern Guangxi, southern China. The new species,Odorranalipuensissp. nov., can be distinguished from its congeners by a combination of the following characters: medium size (SVL: 40.7–47.7 mm in males, 51.1–55.4 mm in females);tips of all but ifrst ifnger expanded with circummarginal grooves; smooth, grass-green dorsum with irregular brown mottling; pineal body invisible; throat to upper abdomen with gray mottling; dorsal surfaces of limbs with brown bands; dorsolateral fold absent; tiny spinules on lateral body, temporal region, and anterior and posterior edge of tympanum;white nuptial pad present on ifnger I; males lacking vocal sacs; females having creamy yellow eggs, without black poles. Uncorrected sequence divergences betweenO.lipuensissp. nov. and all homologous 16S rRNA sequences ofOdorrana available on GenBank is equal to or greater than 4.9%. Currently, the new species is only known from the type locality.展开更多
From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla...From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla. The dominant groups were Araneae, Coleoptera and Hymenoptera, accounting for 48.90% of the total catch. There were 18 common groups and 10 rare groups. The diversity analysis showed that the Banzhai karst cave wetland had the largest soil fauna community diversity index and evenness index and that the Dongsai karst cave wetland had the largest number of groups and individuals. The seasonal variation of the soil fauna in the karst cave wetlands was analyzed: the number of soil fauna individuals showed a downtrend in summer, autumn, spring and winter; there were the highest number of phytophagous soil fauna, followed by predatory soil fauna and saprophagous soil fauna.展开更多
Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. ...Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. Firstly the mechanical model to analysis the stability of cave roof under pile tip is founded aiming to solve the problems that the simplified mechanical model has. Secondly, the boundary of cave roof is simply supposed to be supported according to the integrity of the rock mass in the boundary of cave roof. Thirdly, based on the theory of plates and shells, the simplified model is calculated and the theoretical calculation formula to determine the safe thickness of cave roof under pile tip can be obtained when the edges of the cave roof are simply supported. In the end, the analysis of the practical engineering project proves the feasibility and the rationality of the method which can be a new method to calculate the safe thickness of cave roof under pile tip.展开更多
Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. ...Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. Most of the waters percolating through shilins run through the caves beneath them and are responsible for their formation. The study of cave speleogenesis deepens knowledge about both the development of shilins and karst structure. In the vicinity of the Lunan Shilin, speleological, morphological and structural geological studies of four karst caves have been accomplished. At Puzhehei, Qiubei, which is characterised by numerous fenglin, fengcong and caves, speleological and morphological studies have been performed. Cave sediments for paleomagnetic analyses have been taken from all studied areas (samples CH 1-9). Karst caves in SE Yunnan are probably much older than the age of the cave sediments (<780,000 years B.P.). The studied areas are located in the vicinity of the Xiaojiang fault (N-S direction I and the Red River fault (NW-SE direction). The general directions of both active faults are assumed to influence the direction of the most frequent fissures as well as the cave passages near the Lunan Shilin. The Xiaojiang fault more strongly influences cave passage orientation, while the more distant Red River fault most strongly influences fissure orientation.展开更多
Karst cave tourism plays an important role in the overall tourism of Zhejiang Province,China.In analyzing the current status of karst cave tourism resources,it is crucial to develop a scientific system for optimizing ...Karst cave tourism plays an important role in the overall tourism of Zhejiang Province,China.In analyzing the current status of karst cave tourism resources,it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future.This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province.Nearest neighbor index(NNI) method and accessibility index method were used for a comprehensive understanding of the effects of scale,strength,combination,and accessibility of karst cave tourism resources.Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence,and that resource quality and exploitation are diverse in different regions.Among the regions,Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098.Furthermore,regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets,among which the Lingshan Cave,Fengshui Cave,and Xianqiao Cave reveal the highest accessibility index of 2.41.Finally,we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development.From a regional perspective analysis,the study refined the methods for regional resource research and provided a strategic proposal for karst cave tourism in Zhejiang Province.展开更多
The Baiyun cave is a 380 m long karst cave in the Naigu Shilin, situated 70 km southeast of Kunming, Yunnan Province, China. The prevailing orientations of the cave passages are N110°–120°E and N0°-10&...The Baiyun cave is a 380 m long karst cave in the Naigu Shilin, situated 70 km southeast of Kunming, Yunnan Province, China. The prevailing orientations of the cave passages are N110°–120°E and N0°-10°W and those of the fissures in the cave are N30°–40°W and N20°–30°W. The cave is developed in the thick-bedded Lower Permian Qixia Formation. The cave has an active water flow and is currently at the near water-table stage. There are large amounts of different infills of cave sediments. The cave shows different stages of paragenesis. The palaeomagnetic analysis of cave sediments shows that their ages are younger than 780 ka B.P. (the Brunhes Chron). The upper part of the sampled profile belongs to the reverse Blake event (112.3–117.9 ka B.P.). The formation of the Baiyun cave is directly connected with the development of the Naigu Shilin. The formation of karst underground and surface features depends on the regional tectonic deformation and the Cenozoic extension of the study area.展开更多
Baiyun Cave in the Kongshan Mountain is a cave which developed mostly in thick-layer oolitic limestone of the Middle Cambrain Zhangxia Formation in the Quaternary period.The spatial distribution of the karst cave was ...Baiyun Cave in the Kongshan Mountain is a cave which developed mostly in thick-layer oolitic limestone of the Middle Cambrain Zhangxia Formation in the Quaternary period.The spatial distribution of the karst cave was cotrolled by the NNW,NE and near-EW faults.The karst cave system consists of three layers,includes mainly hall type and corridor type,within which there are diversified sedimentary landscapes and corrosion landscapes,especially"Reticular helictite","Jade-hairpin pointing at bottle","Yin and yang jade columns"and many other special landscapes can hardly be found in other karst caves.Influenced by the strong tectonic activities since the Quaternary period,the cave collapsed several times,and landscapes within the cave have been seriously damaged.Study on the landscape formation of karst caves and influence of cave environment changes on its landscape development will contribute to the reasonable development and protection of tourist resources in the cave.展开更多
[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,...[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,采用Fluent数值模拟软件中的多相流Mixture模型进行不同裂隙数量的溶洞注浆数值模拟,计算模拟注浆时,测试区的注浆压强随时间的变化情况,并与实际工程溶洞注浆压强数据进行对比分析。[结果及结论]对于体积不大于8 m 3的小型非连通型溶洞,其模拟注浆时测试区的注浆压强与裂隙数量呈平方反比关系,注浆压强随着裂隙数量的增加而降低;当裂隙面积达到0.048 m 2时,注浆压强不再降低;注浆压强随着裂隙位置的增高而降低。在实际工程中,可通过对比同类型体积不超过8 m 3小型非连通溶洞之间的注浆压强数据,判断溶洞的相对裂隙数量,调整与优化后续的注浆方案。展开更多
基金Project(50378036) supported by the National Natural Science Foundation of China
文摘According to the engineering features of subgrade cave roof in karst region, the clamped beam model of subgrade cave roof in karst region was set up. Based on the catastrophe theory, the cusp catastrophe model for bearing capacity of subgrade cave roof and safe thickness of subgrade cave roof in karst region was established. The necessary instability conditions of subgrade cave roof were deduced, and then the methods to determine safe thickness of cave roofs under piles and bearing capacity of subgrade cave roof were proposed. At the same time, a practical engineering project was applied to verifying this method, which has been proved successfu1ly. At last, the major factors that affect the stability on cave roof under pile in karst region were deeply discussed and some results in quality were acquired.
基金supported by the Natural Science Foundation of Guangxi Province, China (Grant Nos: 2012GXNSFAA053057, 0832238)the ‘Xibuzhiguang’ Project of Chinese Academy of Sciences
文摘A new species of the genusOdorrana is described from a completely dark karst cave of northeastern Guangxi, southern China. The new species,Odorranalipuensissp. nov., can be distinguished from its congeners by a combination of the following characters: medium size (SVL: 40.7–47.7 mm in males, 51.1–55.4 mm in females);tips of all but ifrst ifnger expanded with circummarginal grooves; smooth, grass-green dorsum with irregular brown mottling; pineal body invisible; throat to upper abdomen with gray mottling; dorsal surfaces of limbs with brown bands; dorsolateral fold absent; tiny spinules on lateral body, temporal region, and anterior and posterior edge of tympanum;white nuptial pad present on ifnger I; males lacking vocal sacs; females having creamy yellow eggs, without black poles. Uncorrected sequence divergences betweenO.lipuensissp. nov. and all homologous 16S rRNA sequences ofOdorrana available on GenBank is equal to or greater than 4.9%. Currently, the new species is only known from the type locality.
基金Sponsored by National Natural Science Foundation of China(31660152)Youth Program Funded by Guizhou Provincial Department of Forestry([2013]10)Guizhou Science and Technology Fund([2013]2135)
文摘From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla. The dominant groups were Araneae, Coleoptera and Hymenoptera, accounting for 48.90% of the total catch. There were 18 common groups and 10 rare groups. The diversity analysis showed that the Banzhai karst cave wetland had the largest soil fauna community diversity index and evenness index and that the Dongsai karst cave wetland had the largest number of groups and individuals. The seasonal variation of the soil fauna in the karst cave wetlands was analyzed: the number of soil fauna individuals showed a downtrend in summer, autumn, spring and winter; there were the highest number of phytophagous soil fauna, followed by predatory soil fauna and saprophagous soil fauna.
基金Project(14JJ4003) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2013M531812) supported by China Postdoctoral Science Foundation+1 种基金Project supported by the Postdoctoral Foundation of Central South UniversityProject(14JJ4003) Project(2013SCEEKL001) supported by Foundation of Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,China
文摘Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. Firstly the mechanical model to analysis the stability of cave roof under pile tip is founded aiming to solve the problems that the simplified mechanical model has. Secondly, the boundary of cave roof is simply supposed to be supported according to the integrity of the rock mass in the boundary of cave roof. Thirdly, based on the theory of plates and shells, the simplified model is calculated and the theoretical calculation formula to determine the safe thickness of cave roof under pile tip can be obtained when the edges of the cave roof are simply supported. In the end, the analysis of the practical engineering project proves the feasibility and the rationality of the method which can be a new method to calculate the safe thickness of cave roof under pile tip.
文摘Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. Most of the waters percolating through shilins run through the caves beneath them and are responsible for their formation. The study of cave speleogenesis deepens knowledge about both the development of shilins and karst structure. In the vicinity of the Lunan Shilin, speleological, morphological and structural geological studies of four karst caves have been accomplished. At Puzhehei, Qiubei, which is characterised by numerous fenglin, fengcong and caves, speleological and morphological studies have been performed. Cave sediments for paleomagnetic analyses have been taken from all studied areas (samples CH 1-9). Karst caves in SE Yunnan are probably much older than the age of the cave sediments (<780,000 years B.P.). The studied areas are located in the vicinity of the Xiaojiang fault (N-S direction I and the Red River fault (NW-SE direction). The general directions of both active faults are assumed to influence the direction of the most frequent fissures as well as the cave passages near the Lunan Shilin. The Xiaojiang fault more strongly influences cave passage orientation, while the more distant Red River fault most strongly influences fissure orientation.
基金Under the auspices of National Natural Science Foundation of China (No. 30571524)
文摘Karst cave tourism plays an important role in the overall tourism of Zhejiang Province,China.In analyzing the current status of karst cave tourism resources,it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future.This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province.Nearest neighbor index(NNI) method and accessibility index method were used for a comprehensive understanding of the effects of scale,strength,combination,and accessibility of karst cave tourism resources.Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence,and that resource quality and exploitation are diverse in different regions.Among the regions,Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098.Furthermore,regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets,among which the Lingshan Cave,Fengshui Cave,and Xianqiao Cave reveal the highest accessibility index of 2.41.Finally,we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development.From a regional perspective analysis,the study refined the methods for regional resource research and provided a strategic proposal for karst cave tourism in Zhejiang Province.
文摘The Baiyun cave is a 380 m long karst cave in the Naigu Shilin, situated 70 km southeast of Kunming, Yunnan Province, China. The prevailing orientations of the cave passages are N110°–120°E and N0°-10°W and those of the fissures in the cave are N30°–40°W and N20°–30°W. The cave is developed in the thick-bedded Lower Permian Qixia Formation. The cave has an active water flow and is currently at the near water-table stage. There are large amounts of different infills of cave sediments. The cave shows different stages of paragenesis. The palaeomagnetic analysis of cave sediments shows that their ages are younger than 780 ka B.P. (the Brunhes Chron). The upper part of the sampled profile belongs to the reverse Blake event (112.3–117.9 ka B.P.). The formation of the Baiyun cave is directly connected with the development of the Naigu Shilin. The formation of karst underground and surface features depends on the regional tectonic deformation and the Cenozoic extension of the study area.
基金Sponsored by National Key Specialized Science&Technology Projects(2011ZX05043-055)
文摘Baiyun Cave in the Kongshan Mountain is a cave which developed mostly in thick-layer oolitic limestone of the Middle Cambrain Zhangxia Formation in the Quaternary period.The spatial distribution of the karst cave was cotrolled by the NNW,NE and near-EW faults.The karst cave system consists of three layers,includes mainly hall type and corridor type,within which there are diversified sedimentary landscapes and corrosion landscapes,especially"Reticular helictite","Jade-hairpin pointing at bottle","Yin and yang jade columns"and many other special landscapes can hardly be found in other karst caves.Influenced by the strong tectonic activities since the Quaternary period,the cave collapsed several times,and landscapes within the cave have been seriously damaged.Study on the landscape formation of karst caves and influence of cave environment changes on its landscape development will contribute to the reasonable development and protection of tourist resources in the cave.
基金国家自然科学基金项目“青藏高原东南缘晚更新世以来地球关键带演化过程”(42361144879)“青藏高原及周缘新生代大陆风化沉积记录研究”(41991323)+4 种基金青藏高原第二次综合科学考察研究任务七“高原生长与演化”专题四“碰撞以来古地理格局与构造地貌过程”(2019QZKK0704)云南省科技领军人才项目“建设云南省地球系统科学重点实验室”(202005AB160008)云南省基础研究计划项目重点项目“滇西南晚更新世和平文化人类植物利用及环境适应性”(202301BF070001-005)兴滇英才支持计划“滇西史前人类植物资源利用及其环境适应性”Queensland-Chinese Academy of Sciences Collaborative Science Fund“Past Asian-Australian MonsoonVariability”(QCAS036,045GJHZ2023001MI)。
文摘[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,采用Fluent数值模拟软件中的多相流Mixture模型进行不同裂隙数量的溶洞注浆数值模拟,计算模拟注浆时,测试区的注浆压强随时间的变化情况,并与实际工程溶洞注浆压强数据进行对比分析。[结果及结论]对于体积不大于8 m 3的小型非连通型溶洞,其模拟注浆时测试区的注浆压强与裂隙数量呈平方反比关系,注浆压强随着裂隙数量的增加而降低;当裂隙面积达到0.048 m 2时,注浆压强不再降低;注浆压强随着裂隙位置的增高而降低。在实际工程中,可通过对比同类型体积不超过8 m 3小型非连通溶洞之间的注浆压强数据,判断溶洞的相对裂隙数量,调整与优化后续的注浆方案。