Study On The Method Of Geometrical Information Acquisition Of Rock Mass Discontinuities Based On Digital Close Range Photogrammetry

Nowadays, with the continuous development of large-scale infrastructureconstruction in China，more and more project construction of water conservancy andhydropower， railway， transportation and other fields gradually to mountaindevelopment，because of the complex structure of mountain rock，so the stability ofhigh slope rock mass and wall rock during tunnel excavation is essential for thesmooth construction projects and life and property safety of people. To analysis andevaluate the stability of rock mass，which determine the smooth development andimplementation of conduct construction， and the Important security factor ofobtaining project benefit. Obtaining discontinuities of rock mass is the key forevaluating the stability of rock mass. Aiming at the disadvantages and unfavorablefactors in the conventional method of obtaining the rock mass discontinuities afterhigh slope rock mass and wall rock during tunnel excavation, the application ofobtaining rock mass discontinuities in digital close range photogrammetry method,that can solve these problems quickly, efficiently, and provide a new way for obtaininformation of rock mass and stability analysis of rock mass structural, which has theimportant research significance.In this paper, Changchun the moon lake Yangjiagou Quarry and rock massmechanics Jilin University tunnel practice base for the experimental site, combinedwith some characteristics of tall steep slope, tunnel operation condition of Limited, onthe basis of the using a large number of non—prism total station on the field datacollection, application of rock mass non-contact measurement technology to obtaininformation of rock structural surface control point, and through common digitalcamera shooting, which obtain the image data of rock slope and tunnel. Based on therelevant principles of digital close-range photogrammetry and computer vision field, using the VirtuoZo digital photogrammetric workstation, the focuses on theestablishment method of the quarry high and steep slope dimensional model, and thework of information interpretation and evaluation of the accuracy of the model; at thesame time, aiming at the characteristics of tunnel narrow space, no lighting conditions,to establish the direction of tunnel face using Lensphoto multi baseline digital closerange photogrammetry software model, as well as the model accuracy assessment andtunnel rock mass discontinuities information extraction. Though the3D model of therock mass slope and tunnel, accuracy assessment, geometric informationinterpretation, which provide a comprehensive, reliable, full and accurate data for thestability evaluation of rock mass structure. The main contents of this paper are asfollows:1. Field control survey data acquisition from the method of non prism totalstation space polar coordinate. Research on the control of measuring and gradingdistribution principle, rock mass structural plane control point principle, method ofnon prism total station space polar coordinate, accuracy evaluation of field controlsurvey data acquisition, control point measurement error within±4mm, can providereliable data for the establishment of three-dimensional model of slope, and analyzingnon prism total station measuring direction and the angle between the structural planetolerance. Through the non prism total station with different measurement station anddifferent contrast data plane control point measurement station, analysis of non prismtotal station measuring direction and the structural plane angle is greater than30°;2. Slope and tunnel excavation face image acquisition and correction. To shootordinary SLR digital camera, take the approximate slope honest way of photography,shooting tunnel adopt a multi-way rotary baseline, respectively, to obtain image dataand based on the principles of computer vision research related to digital cameracalibration and image correction, based on the relationship between the actual imagepixel coordinates to draw contrast image correction after correction amount with thesame diameter as the point of the curve, and quantitative analysis of image correction,increase the understanding of people to quantify the corrections of the images;3. Slope and tunnel excavation face establish a three-dimensional model. Basedon the image data control point data acquisition and calibration of field controlmeasure. Use VirtuoZo digital photogrammetric workstation to build athree-dimensional model of a tall rock slope, discussed the technical process andmethod of VirtuoZo three-dimensional model establishement of the slope. Use Lensphoto multi-baseline digital close-range photogrammetry software to build athree-dimensional model of the working face of the tunnel;4. The accuracy of the model evaluation. Interpretation of3D model information,contrast control coordinate through field tests and laboratory interpretation, using theerror theory analysis on the modeling of control points of measurement precision andnon model control interpretation precision of points within±3cm; the total station fourpoint method to calculate occurrence and model analysis results the occurrenceinformation, calculate the tendency, inclination error is±5°and±4°, whih betterprecision, the reliability of the occurrence information solution evaluationmeasurement error model.5. A lot of interpretation of rock mass structural plane geometry information.Under the premise of the model accuracy to meet the requirements, a solution ofstructural plane of rock mass geometry information translation model, provideabundant, reliable, accurate data for the evaluation of structural plane of rock massstability.Research findings have important theoretical and practical significance of theproject.