Rapid Identification Of Joints And Fractures And 3D Characterization Of Rock Mass Quality

With the continuous development and utilization of underground space in China,urban subways,highways,railways,mining projects and other projects are increasing.In the construction process of these engineering projects,it is often possible to encounter collapse accidents caused by the instability of rock mass after tunnel excavation.Therefore,how to efficiently evaluate the stability of rock mass quality and how to visually display the quality status of rock mass in three dimensions has become a hot research topic.In this paper,under the support of the National Natural Science Foundation Project No.51874112,a crack identification program based on MATLAB was developed to extract the crack information in close-range photography photos.By relying on the actual mine projects,the dynamic classification of rock mass quality and its three-dimensional visualization were realized.The main research results and conclusions of this paper are as follows:(1)The digital close range photography method overcomes the shortcomings of the traditional fracture statistical measurement method,and provides a feasible way to achieve efficient and accurate fracture parameter measurement.Starting from the aspects of digital image processing,illumination influence and scale deviation correction,the methods of manual processing and identification of joint geometric information in close-range photography photos and automatic identification of close-range photography to extract the geometric information of fissure joint are obtained respectively.For the demand of huge amount of data in the project,the advantages of artificial crack identification in close-range photography with lower requirements on the quality of close-range photography are highlighted.For data updating requirements and fast acquisition of rock mass quality requirements,automatic crack identification program is more convenient.(2)The new method of fine and efficient rock mass quality identification will promote the popularization and application of the results of rock mass quality quantification.Based on the actual project of an iron mine in South China,a rock mass quality evaluation method and system based on close range photography is proposed to optimize the traditional rock mass quality evaluation method,which verifies the feasibility of fracture identification,realizes the automation of rock mass quality evaluation,and independently develops the engineering rock mass quality grade evaluation and three-dimensional visual management system,which effectively avoids the occurrence of human operation error It greatly improves the efficiency and accuracy of rock quality grade evaluation.(3)The quality grade and spatial distribution of rock mass can provide scientific basis for production optimization design.According to the solid model of ore body and surrounding rock,the three-dimensional block model suitable for a specific mine is established.The sample points of rock mass quality index value in the area to be evaluated are established by combining the RMR of each survey point with the field coordinates.The three-dimensional rock classification model of the mine is obtained by the distance power inverse evaluation method to assign the three-dimensional block model to realize the rock mass quality classification The three-dimensional visualization of rock mass quality is carried out by cutting the three-dimensional distribution model of rock mass quality,and the distribution of rock mass grade at all levels is obtained,and the distribution of rock mass quality grade in all areas including uncovering area is determined and displayed intuitively and quickly.This method can help to fully understand the regional geological situation,provide guidance for the production and design of underground engineering,and provide the basis for the safety construction of underground engineering.