Research On Stability Analysis And Environmental Bearing Capacity Calculation Of Karst Cave Rock Mass Based On TL

Karst cave is a very precious tourism resource formed under long-term geological action and is a typical intangible cultural heritage.However,there are some phenomena in the development of karst caves,such as insufficient investigation in the early stage and chaotic lighting arrangement,which cause great damage to the landscape of karst caves.As the key factors of sustainable development of karst caves,rock stability analysis and environmental bearing capacity calculation can provide data and reference for tourism route planning and design of karst caves.At the same time,3D laser scanning technology can obtain 3D point cloud of objects with high precision and fast,which has great application prospect.Therefore,based on three-dimensional laser scanning technology,this paper studies the rock mass stability analysis method and environmental bearing capacity calculation of karst caves,and actively explores the application of three-dimensional point cloud and model in karst caves.The main research contents and achievements are as follows:Establish a fine three-dimensional model of karst caves.The unique advantages of TLS technology in high efficiency and high precision data collection in complex environments were utilized to obtain the three-dimensional point cloud data of caves,and the improved ICP registration and statistical filtering were carried out for denoising.The detailed three-dimensional model of caves was established to provide basic data and model support for environmental bearing capacity calculation and rock mass stability analysis.Based on the three-dimensional point cloud of karst cave,the stability analysis method of the main structure of the cave is proposed to identify the structural plane of rock mass.For the cave main point cloud,the correct KNN search algorithm and PCA algorithm are used to calculate the normal vector of the point cloud effectively.On this basis,FACET geological structure plug-in is used to automatically recognize and extract structural plane information of karst cave main body.Combined with KDE algorithm,DBSCAN algorithm and kinematic analysis,the influence of structural plane development on cave passage and rock mass development is studied.Based on the three-dimensional model of karst caves,an improved ecoenvironmental capacity method is proposed to effectively calculate the maximum tourism capacity of karst caves.According to the requirements of tourism cave planning and design,the existing cave three-dimensional model is segmented and the tourism space model is established.On this basis,considering CO2 concentration,heat,water flow,light and other factors affecting cave environment,the traditional ecological environment capacity method was improved,and a mathematical model of environmental carrying capacity based on three-dimensional model was established to effectively calculate tourism capacity.Compared with the traditional method,this method can effectively avoid the generation of virtual tourists,and the result is more in line with the actual situation.Taking Sanjiao Cave in Jiuxiang,Yiliang,Yunnan Province as an example,the rock mass stability analysis of the typical area shows that the interior of the Sanjiao Cave is relatively stable and the possibility of failure is small,which is characterized by no plane sliding or wedge sliding risk.However,toppling failure may occur in local areas,with the maximum probability of 19.64% and the minimum probability of10.07%.In addition,based on the three-dimensional model of the three-legged cave,the instantaneous carrying capacity of the three-legged cave is 16311 people and the all-day carrying capacity of the three-legged cave is 212,043 people without changing other conditions.Compared with the existing methods,the maximum difference of instantaneous carrying capacity is 19,146 people,and the maximum difference of allday carrying capacity is 123189 people.Therefore,the rock mass stability analysis and environmental bearing capacity calculation method based on TLS technology can not only assist the geological investigation and analysis of karst caves,but also effectively identify rock mass structural plane,carry out numerical simulation of rock mass stress and reduce field workload.At the same time,it provides a reference for the planning and design of tourist routes,and serves as the basis for the follow-up monitoring of tourist flow in karst caves.