Quality Evaluation Of Rock Mass Based On Close-range Photogrammetry To Structural Plane Information

With the continuous construction of various heavy and large projects in China,rock mass stability analysis and quality evaluation are the basic work of all kinds of engineering construction.Before rock mass quality evaluation,a large number of geometric information of rock mass structural plane should be obtained.The traditional geometric information of structural plane is mainly obtained by manual contact measurement.It is a commonly used method of structural plane measurement,which has the advantages of large field strength and time-consuming and energy-consuming.Due to the influence of bad working environment and other shortcomings,manual contact measurement methods are greatly limited.With the continuous development of photogrammetry technology,digital close-range photogrammetry technology has been applied to engineering geological survey.As a non-contact survey,digital close-range photogrammetry has It is fast and can obtain a lot of information,which makes up for the deficiency of traditional manual contact measurement.Through a large number of theoretical research and practice,a large number of geometric information of rock mass structural plane can be obtained based on close-range photogrammetry technology,which provides data for stability analysis and evaluation of engineering rock mass.The probability density distribution of geometric parameters of structural plane is supported by the study of structural plane properties,random simulation of three-dimensional network,division of statistical homogeneous zone,reliability design of rock mass engineering and so on.In the study of rock mass engineering problems,it is considered that the parameters of structural plane obey the normal distribution,which is artificial subjective and can not reflect the diversity characteristics of the distribution of characterization parameters determined by the complex structure of rock mass.It is of great scientific significance to study the probability distribution of geometric parameters of rock mass structure by using probability theory and random mathematical theory.The main work of rock mass stability analysis is rock mass quality evaluation.The factors affecting rock mass quality are lithology,rock mass integrity,rock mass structure,weathered degree,groundwater and ground stress.According to the different factors considered,rock mass quality evaluation can be divided into qualitative,quantitative,semi-quantitative,single-factor and multi-factor methods,such as RMR classification,Q system,RQD,CSMR classification and so on.With the continuous development of computer technology,many new methods and new theories have been applied to rock mass quality evaluation,such as fuzzy mathematics theory,extension theory,cloud model,fractal geometry and so on.The evaluation methods are different.Quasi It is of great significance to determine the quality grade of rock mass quickly for rock mass engineering construction.Based on digital close-range photogrammetry technology,taking the abandoned quarry slope of Dongsheng Village in Jingyue Development Zone of Changchun City as an example,the geometric parameters of random structural plane of rock slope are obtained in this paper.Based on the obtained geometric parameters,the hypothesis test method is used to test the hypothesis,and the probability distribution statistics of the geometric parameters of the structural plane are carried out.The optimal fitting degree is introduced to determine the optimal fitting probability for the case of obeying various distribution functions.For the data that do not obey any distribution function,the maximum and minimum are removed and further verified.Based on the traditional RMR,Q classification,RQD,fuzzy mathematics theory,extension theory,cloud model and fractal theory,respectively.The evaluation of slope rock mass quality is put forward,and the traditional grid method is improved to calculate fractal dimension,which makes it more convenient to calculate fractal dimension.Finally,according to RQD,a rock mass quality evaluation method with fractal dimension as index is established.The research results of this paper are as follows:(1)The geometric parameters of random structural surface are obtained based on digital close-range photogrammetry.The 3D model of slope is established by VirtuoZo platform,and the geometric parameters of slope structural plane are obtained by calculating the parameters of rock mass structural plane,which provides the data for rock mass quality evaluation.(2)K-S hypothesis test of geometric parameters of structural surface.The two-dimensional trace obeys the logarithmic normal distribution,the occurrence obeys thegamma distribution,the Rayleigh distribution,the normal distribution,the Poisson distribution,the optimal fitting degree calculates,the xoy,xoz plane spacing obeys the logarithmic normal distribution,the occurrence obeys the gamma distribution,and the occurrence obeys the gamma distribution.The maximum and minimum values of yoz surface spacing data are removed and the logarithmic normal distribution is obeyed,and the three-dimensional trace obeys the logarithmic normal distribution after removing the maximum and minimum values.(3)The establishment of rock mass quality evaluation index based on fractal dimension.The fractal dimension of slope is calculated by square grid method and long grid method respectively.because the fractal dimension is affected by scale-free interval,the scale-free interval is determined according to the method of manual discrimination,and the final fractal dimension is obtained.The linear relationship is established with the calculated RQD value,and the rock mass quality evaluation system with fractal dimension as the index is obtained,and the rock mass grade of the experimental slope is determined to be grade II.(4)Evaluation of rock mass quality of experimental slope.Based on RMR classification,Q system and fuzzy mathematics theory,the rock mass quality evaluation of slope rock mass is grade III,extension theory,cloud model slope rock mass quality evaluation results are grade?,comprehensively speaking,the rock mass quality of experimental slope is between grade?and grade III.evaluation method based on fractal dimension is established.