Karst Cave Tourism System in Zhejiang Province Based on Resource Regional Analysis

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 re- search and provided a strategic proposal for karst cave tourism in Zheiiang Province.

An attribute recognition model for safe thickness assessment between concealed karst cave and tunnel

An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.

Collapse mode of rock mass induced by a concealed karst cave above a deep cavity

Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the effect of the blast vibration, a possible collapse would occur at a certain region between the concealed karst cave and the excavated cavity. This paper aims to study the roof collapse of a deep buried cavity induced by a concealed karst cave base on a two-dimensional failure mechanism by using upper bound theorem. The failure mechanism is constituted by arbitrary curves which is similar to the collapse observed in an actual cavity excavation. The shape and range of the collapse block is determined by virtual work equation in conjunction with variational approach. The results obtained by the presented approach are approximate with the numerical results provided by finite difference code, which indicates that the proposed method in this work is valid.

A New Species of Odorrana Inhabiting Complete Darkness in a Karst Cave in Guangxi, China

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.

Comprehensive Analysis of the Influential Factors of Karst Cave Tourism Development

There are many karst caves in China and each karst cave is a special part of natural landscape resources.How to exploit karst cave resources to develop tourism relates to the the effective exploitation of karst caves resources.The author comprehensively analyzed the main influential factors of karst cave tourism development and concluded that the influential factors were the feature of karst caves resources,transportation condition,construction condition,regional economic development level,source market,regional combination of scenic spots,spatial competition,investors' decision-making behavior,local residents' attitudes and so on.The integrated action of these factors codetermines whether karst cave tourism development successes or not.Only by thoroughly realizing the status and role of every influential factor karst cave tourism development could be reasonably conducted,exploiting strong points and avoiding shortcomings.

The Diversity of Soil Fauna Communities in the Karst Cave Wetland of Maolan Nature Reserve

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.

Formation of Baiyun Karst Cave Landscapes in the Kongshan Mountain of Lincheng County, Hebei Province

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.

Assessment and optimization of fracture-karst cave connectivity in horizontal well hydraulic fracturing of carbonate reservoirs

The karst cave serves as the primary storage space in carbonate reservoirs.Simultaneously connecting multiple karst caves through hydraulic fracturing is key to the efficient development of carbonate reservoirs.However,there is lack of systematic research on the mechanisms and influencing factors of fracture propagation in car-bonate rocks.This paper established models including karst cave models,single natural fracture-cave models,and multiple natural fracture-cave models based on the discrete lattice method.It thoroughly studied how geological and operational factors affect the fracture propagation and the connectivity of karst caves.The final step involved establishing a prototype well model and optimizing operation parameters.The research indicates that an increase in the Young's modulus and pore pressure of karst cave could facilitate hydraulic fracture connecting with caves.When the pore pressure is lower than that in the matrix,it will generate a repulsive effect on hydraulic fractures.The natural fracture along the hydraulic fracture path significantly facilitates the connection with caves.When the wellbore azimuth is less than 60℃,the fracture's diversion radius is small,and hydraulic fractures primarily connect with karst cave through natural fractures.When the wellbore azimuth exceeds 60℃,the fracture's diversion radius increases.Under the combined action of hydraulic fractures and natural fractures,the stimulated volume of the karst cave noticeably increases.Under the same liquid volume,increasing the injection rate could enhance the cave stimulated volume.Combining the findings from numerical simulation studies resulted in the development of a diagram that depicts the connectivity of karst caves,providing valuable insight for hydraulic fracturing operations in carbonate reservoirs.

Influence of CO_(2)/HCO_(3)^(-) on Microbial Communities in Two Karst Caves with High CO_(2)

There is limited knowledge about microbial communities and their ecological functions in karst caves with high CO_(2)concentrations.Here,we studied the microbial community compositions and functions in Shuiming Cave( "SMC",CO_(2)concentration 3 303 ppm) and Xueyu Cave( "XYC",CO_(2)concentration 8 753 ppm) using Illumina MiSeq high-throughput sequencing in combination with BIOLOG test.The results showed that Proteobacteria,Actinobacteria and Bacteroidetes were dominant phyla in these two caves,and Thaumarchaeota was the most abundant in the rock wall samples of SMC.The microbial diversity in the water samples decreased with increasing HCO_(3)^(-)concentration,and it was higher in XYC than that in SMC.The microbial community structures in the sediment and rock wall samples were quite different between the two caves.High concentrations of CO_(2)can reduce the microbial diversity on the rock walls in karst caves,probably through changing microbial preference for different types of carbon sources and decreasing the microbial utilization rate of carbon sources.These results expanded our understanding of microbial community and its response to environments in karst caves with high CO_(2).

Discovery of the ancient Ordovician oil-bearing karst cave in Liuhuanggou,North Tarim Basin,and its significance

A typical ancient karst cave is found in the Yijianfang Formation of Ordovician at Liuhuanggou,North Tarim Basin.With an entrance of 4.8 m wide and 20 m high,the Liuhuanggou ancient karst cave extends to NW 315° and has been filled by sediments,which can be classified into three types according to their nature and origin:clastic sediments(gravels),chemical sediments(palaeotravertine),and mixed sediments.Among them,the Paleotravertine and gravels are most common.The palaeotravertine is laminated type and yellowish brown or black in color due to oil inside.When saturated with oil,the palaeotravertine is black.Under microscope,oil mainly accumulates in the cracks between calcite crystals.The filling period of the Liuhuanggou karst cave can be divided into three stages:mixed filling,chemical filling,and clastic(palaeotravertine breccia) filling.Numerous fractures are distributed on one side of the karst cave.The fractures can be as wide as 40 cm and over 40 m long.Fractures of different periods and sizes constitute a fracture network and are all filled with calcite veins.Oil can be found inside the fractures.In the chemical fillings,sulfur is also found,which can indicate the magma influence on karst caves.The existence of sulfur also confirms that the Liuhunggou karst cave was formed in ancient times rather than recently or nowadays.Different from normal sedimentary limestone,the ancient Liuhuanggou karst cave has a distinct isotope fractionation and the depletion of heavy carbon and oxygen isotope.Controlled by the northwest oriented vertical strike-slip shear fault,the karst cave is actually a dissolved vertical fault belt.

The spatial distribution and factors affecting karst cave development in Guizhou Province

This research examines the distribution features of 4960 caves across Guizhou Province, while probing the relationship between the caves＇ spatial patterns and geographic elements. This study is based on hydrogeological and topographic maps of Guizhou. ArcGIS software was used to process the adjacent index, spatial analysis, and coupling analysis of the caves altitude and longitude, as well as the rock properties, lithology, drainage and tec- tonic division of almost 5000 caves. Based on a point pattern analysis of Guizhou caves, the adjacent index is 0.53, and the coefficient of variation verified by Tyson polygon reached 72.469%. This figure reflects the clustered distribution pattern of the caves. Across the entire province, caves are divided into four concentrated areas and one weakly affected area. The four concentrated areas are Zunyi-Tongren, Bijie, Qianxinan-Liupanshui, and Gui- yang-Anshun-Qinan. The one weakly affected zone is Qiandongnan. The most concentrated among them is the Guiyang-Anshun-Qiannan area, which covers 24.67% of the total province area, and accounts for 36.63% of the total province＇s caves. Cave distribution in Guizhou is characterized as dense in the western part and sparse in the eastern part. Under this study background, the natural elements of formation, including lithology, structure, climate, hydrol- ogy, and altitude, and their effects on the distribution, number, and spatial pattern of cave development is analyzed.

Culturable mycobiota from Karst caves in China II,with descriptions of 33 new species

Karst caves are characterized by darkness,low temperature,high humidity,and oligotrophic organisms due to its relatively closed and strongly zonal environments.Up to now,1626 species in 644 genera of fungi have been reported from caves and mines worldwide.In this study,we investigated the culturable mycobiota in karst caves in southwest China.In total,251 samples from thirteen caves were collected and 2344 fungal strains were isolated using dilution plate method.Preliminary ITS analyses showed that these strains belonged to 610 species in 253 genera.Among these species,88.0%belonged to Ascomy-cota,8.0%Basidiomycota,1.9%Mortierellomycota,1.9%Mucoromycota,and 0.2%Glomeromycota.The majority of these species have been previously known from other environments,and some of them are known as mycorrhizal or pathogenic fungi.About 52.8%of these species were discovered for the first time in karst caves.Based on morphological and phyloge-netic distinctions,33 new species were identified and described in this paper.Meanwhile,one new genus of Cordycipitaceae,Gamszarea,and five new combinations are established.This work further demonstrated that Karst caves encompass a high fungal diversity,including a number of previously unknown species.Taxonomic novelties:New genus:Gamszarea Z.F.Zhang&L.Cai;Novel species:Amphichorda cavernicola,Aspergillus limoniformis,Aspergillus phialiformis,Aspergillus phialosimplex,Auxarthron chinense,Auxarthron guangxiense,Auxarthronopsis globiasca,Auxarthronopsis pedicellaris,Auxarthronopsis pulverea,Auxarthronopsis stercicola,Chrysosporium pallidum,Gamszarea humicola,Gamszarea lunata,Gamszarea microspora,Gymnoascus flavus,Jattaea reniformis,Lecanicillium magnisporum,Microascus collaris,Microas-cus levis,Microascus sparsimycelialis,Microascus superficialis,Microascus trigonus,Nigrospora globosa,Paracremonium apiculatum,Paracremonium ellipsoideum,Paraphaeosphaeria hydei,Pseudoscopulariopsis asperispora,Setophaeosphaeria microspora,Simplicillium album,Simplicillium humicola,Wardomycopsis dolichi,Wardomycopsis ellipsoconidiophora,Wardomycopsis fusca;New combinations:Gamszarea indonesiaca(Kurihara&Sukarno)Z.F.Zhang&L.Cai,Gamszarea kalimantanensis(Kurihara&Sukarno)Z.F.Zhang&L.Cai,Gamszarea restricta(Hubka,Kubátová,Nonaka,Čmoková&Řehulka)Z.F.Zhang&L.Cai,Gamszarea testudinea(Hubka,Kubátová,Nonaka,Čmoková&Řehulka)Z.F.Zhang&L.Cai,Gamszarea wallacei(H.C.Evans)Z.F.Zhang&L.Cai.

Zinc phosphate dissolution by bacteria isolated from an oligotrophic karst cave in central China

Biogeochemical processes are fundamental to sustain the ecosystem in subsurface caves, but to date they are still far from well understood. To investigate micro-bially mediated phosphorus and zinc cycles, we isolated three bacterial strains from the dripping water in Heshang cave, central China, identified as Exiguobacterium aurantiacum E11, Pseudomonas fluorescens P35, and Pseu- domonas poae P41, respectively. Microbial capabilities in the dissolution of phosphorus-containing minerals were tested with zinc phosphate （Zn3（PO4）2） in batch culture at 30~C. A spectrophotometer, atomic absorption spectrum, and scanning electronic microscopy were used to measure the microbial growth, soluble Zn（II） concentration, and to observe the morphology of Zn3（PO4）2 before and after microbial dissolution. P. fluorescens and P. poae, the well- known phosphorus solubilizing bacteria （PSB）, are observed to solubilize Zn3（PO4）2 with an efficiency of 16.7% and 17.6%, respectively. To our knowledge, E. aurantiacum is firstly reported in this study to dissolve phosphorous-containing minerals with a higher efficiency of 39.7%, expanding our understanding about the ubiquitous occurrence of PSB in natural environments. Aqueous Zn（II） concentration positively correlates with H＋ activity, confirming the presence of acidification mechanisms widely exploited by PSB. Few itching pits were observed on the surface of Zn3（PO4）2 after microbial dissolution, inferring that microbial dissolution is not always associated with the direct contact with minerals. Even though the soluble Zn（II） concentration reached up to 370 mg/L in the system inoculated with E. aurantiacum Ell, inhibition of microbial growth was not detected by spectrophotometer. Our laboratory data revealed the importance of microbially-mediated P and Zn cycles in the subsurface ecosystem.

Stability analysis on tunnels with karst caves using the distinct lattice spring model

The effects of karst caves on tunnel stability were numerically investigated using the distinct lattice spring model(DLSM).The DLSM was validated by investigating the mechanical behavior of Brazilian discs with various sizes of central circular holes.Then,the effects of karst cave on U-shaped tunnel were investigated under various karst caves positions(top,bottom,and right side of the tunnel),tunnelcave distances(0.5-4 times the radius of the tunnel arc),and cave shapes(circular,rectangular flat,and rectangular vertical caves).The failure processes of the tunnel under those various conditions were analyzed and both the failure process and the final failure patterns of the tunnel were discussed.Numerical simulation demonstrated that karst caves around the tunnel could weaken the stability of the tunnel,indicating tunnel-cave distance effects.The closer the cave to the tunnel,the weaker the tunnel under loading.This effect was not significant when the tunnel-cave distance(d)was larger than three times the tunnel arc radius(R).In addition,the final failure pattern of the tunnel and its surrounding rock mass were dependent on both the position and the size of the cave.The larger the cave,the weaker the tunnel and its surrounding rock mass.Furthermore,compared with those cases with top and bottom caves,the tunnel with a right side cave had more impacts on tunnel stability.The main research finding could help engineers carry out stability analysis on tunnels in karst areas and take effective measures to enhance tunnel stability.

Analysis of the Mechanism of Water Inrush Geohazards in Deep-Buried Tunnels under the Complex Geological Environment of Karst Cave-Fractured Zone

To study the mechanism and evolution process of water inrush geohazards under the complex geological environment of the karst cave-fractured zone,a large-scale physical threedimensional(3 D)model test was first performed.Then the conceptual model for the evolution process of water inrush geohazards and the simplified theoretical model for the critical hydraulic pressure were both established based on the main characteristics of the water inrush geohazard in the engineering background and that in the model test.A new method was developed for modeling the geological environment of the karst cave-structural plane,and two formulae describing the critical water pressure of water inrush geohazards under two failure models of tensile-shear fracture failure and compressionshear fracture failure were also deduced based on fracture mechanics.The results showed that:(1)the evolution process of the water inrush geohazard can be divided into four stages,which include the initial balance,the propagation of original cracks,the formation of the dominant water inrush channel,and the instability of the waterproof rock mass;(2)the suddenness of water inrush geohazards becomes stronger with the increase of the hydraulic pressure;(3)the calculated critical hydraulic pressure of water inrush geohazards is similar to the measured critical hydraulic pressure in the model test,which validated the accuracies of the theoretical model,and the failure model of water inrush geohazards in this research is compression-shear fracture failure.

Baiyun Cave in Naigu Shilin,Yunnan Karst,China

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.

Discovery of Middle Pleistocene Mammal Fauna From Tangshan Karst Cave, Nanjing and Its Significance

The material reported in this note was collected from Huludong (Calabash Cave), a karst cave at the northeastern extremity of Tangshan Hill, Nanjing. The cave is located on the hillside to the south of the Nanjing-Hangzhou Highway near the west verge of the Tangshan Town, Jiangning County, 26km east of the centre of Nanjing (32°N and 119°E). The bottom of this cave is 85.9m above sea level, with a relative height of about 75m from the local highway. This karst cave developed in the Ordovician limestone assumes the shape of an east-westward extending calabash, about 80m long,

Stability analysis of subgrade cave roofs in karst region

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.

Speleogenesis of Selected Caves beneath the Lunan Shilin and Caves of Fenglin Karst in Qiubei, Yunnan

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.

深埋岩溶隧道爆破开挖对围岩损伤及渗流特性的影响

深埋岩溶隧道开挖会造成围岩特殊的损伤破坏形式,并且损伤区也会影响围岩渗流场及隧道边界的涌水状况,对深埋岩溶隧道爆破开挖作用下围岩的损伤及渗流特性有重要的研究意义。为了研究爆破开挖对深埋岩溶隧道围岩损伤及渗流的影响规律,基于COMSOL Multiphysics软件建立数值模型并嵌入应力-渗流-损伤耦合方程式进行计算,采用解析法计算了简化条件下岩溶隧道开挖时围岩的应力分布,并与数值计算结果进行比较。结果表明:解析法与数值法计算的围岩应力分布有一致性,爆炸荷载使靠近溶洞侧隧道肩部及脚部区域会产生较大的拉应力;爆破后会在隔水岩柱形成“齿”状损伤区,同时引起肩部及脚部区域流速的增加,其可作为判断溶洞方位的参考依据;溶洞净距减小、洞径及水压增加会引起“齿”延伸倾角及最大涌水位置变化、隧道边界涌水量的增加,可根据“齿”延伸方向判断损伤区检测的合理方位,根据最大涌水位置变化、隧道边界涌水量的变化,合理调整涌水防治措施强度及重点防治部位。研究成果可为溶洞位置判定、隧道损伤区检测以及边界涌水防治措施提供参考。