| Stability research of lithesome engineering is one of the important problems in engineering geological analysis, rock mechanics and rock structural mechanics. Rock mass discontinuity is the crucial factor of rock stability. Rock mass structure is presented as a composite geological structure forming of structural surface and rock mass in certain geological conditions. Structural surface is two-dimension plane geological interface with certain direction, low mechanics intensity and low thickness. The existence of structural surface makes rock mass show uncontinuity, inhomogeneity and anisotropy. Rock mass stability closely relates to features of structural surface. As a result, it is crucial important to collect structural surface information rapidly with high precision, which also has real significance to exploration, engineering design, geological engineering evaluation and risk forecast.The acquisition method of rock mass discontinuity information can be categorized as contact type and non-contact type. Contact type acquisition method includes drilling and compass measure. Non-contact type acquisition method includes three-dimensional laser scanning and photogrammetry. Although compass measure is a frequently utilized simple and precise method for rock mass discontinuity information acquisition, it takes much time and manpower. Considering some high side slope or rugged environment, surveyor cannot close to rock surface because of high fatalness. Moreover, the imbalance of surveyor quality may make the inaccurate of surveying result. Three-dimensional laser scanning and drilling method is too expensive to be applied widely or cannot capture precise information of crack which makes them not applied well. However, photogrammetry attracts broad attention from international researchers and achieved some important research result because of its rapid, comprehensive, non-contact and some other characteristics for rock mass discontinuity information acquisition.The article is based on the tutor's national natural science project(40472136) and (40872170). On the basis of full rock fractures information investigation and research, against second quarry at Jingyue North Mountain's lithologic slope in Changchun, digital close range photogrammetry is used in the rapid acquisition and the application research of discontinuities information. In this paper, with conducted research, we discussed the feasibility, precision, working mode of using digital close-range photogrammetry to acquire lithesome side slope structural surface information rapidly. In our research, ordinary single-lens reflex digital camera was used as sensor to get side slope imageries, which is based on the field three-dimensional control surveying using non-prism laser total station, mobile control system, Interpretation was realized on VirtuoZo, a digital photogrammetry workstation, to get three-dimensional spatial coordination of lithesome structural surface feature points, which were the origin of rock mass track information. On this basis, combining the attitude calculation model, we calculated the attitude of lithesome structural surface researched to get its three-dimensional track information. By analyzing control points position and attitude interpreted, it was proved to be feasible to get lithesome crack fissure information by using digital close-range photogrammetry. On the base of fissure information statistics, categorizing of rock mass structure predominant group number and stereographic projection side slope stability analysis were conducted, taking second quarry at Jingyue North Mountain as a case study. Results are listed as following.1. Aiming the requirement of fast construction and difficult-to-touch characteristics of high side slope, a control surveying method of collecting rock mass structural surface three-dimensional coordinate was realized using non-prism laser total station and polar coordinates method. During the fieldwork control surveying, compass surveying was combined to build three-dimensional spatial coordination system using magnetic north as vertical axis. Only a non-prism laser total station and a tripod are needed to fulfill acquiring of rock mass side slope structural surface feature points' coordinate. Easy operation, rapid observation, non-office-work are characteristics of this method, which make it has good application value in practical job.2. Checking and calibration method of non-prism laser total station was researched. Forward intersection method was used to check plane precision and ruler with known length was used to check ranging precision.3. Digital photography scheme using ordinary single-lens reflex for rock mass structural surface information rapid acquirement was research. Photography mode, baseline distance (always 1/5 ~ 1/10) and matters needs attention were presented. The advantages and disadvantages of digital close-range photogrammetry were provided by the comparison between ordinary single-lens reflex digital camera and ordinary home-use camera.4. By using VirtuoZo digital photogrammetry workstation to process rock mass side slope imageries, we studied the method and workflow for rock mass structural surface characteristic information, which provide a new research direction for rock mass fissure information rapid collection, rock mass structural surface information was interpreted at Jingyu north mountain quarry, with photography distance of 40m, photography baseline of 5m, control point precision of 5mm and baseline parallel with side slope direction, which made an approximate vertical image pair. By comparing interpreted attitude with compass measured data, the error of fitting is less than 7°.5. On the base of characteristic point information of rock mass fissure collected by close-range photogrammetry, we presented a fitting plan equation to build structural surface based on least square method. It was used to build attitude model of rock mass structural surface with corresponding normal vector. On Matlat programming platform, a numerical model program was made. In research, to calculate rock attitude, three points method was used with big structural surface and multipoint least square method with small, long narrow structural surface.6. Statistical analysis was conducted using survey error theory on attitude data measured by field compass contact method. It shows that the single measure has the mean square error of 4°with dip direction and 3°with dip angle. The limited error of compass measure can be defined as 12°with dip direction and 9°with dip angle. It can be used as the error limitation to assess precision of attitude measured by digital close-range photogrammetry.7. Precision analysis was made on attitude measured by digital close-range photogrammetry. We compared the measure precision between digital close-range photogrammetry and compass measure. Considering different camera resolution and overlap area of adjacent image pair, it shows:1) By using digital close-range photogrammetry , the mean square error is±6°with dip direction,±5°with dip angle and±7°with fitting, comparing with the±5°mean square error of compass measure. If we define error limitation as 2 times of mean square error, attitude measured by digital close-range photogrammetry workstation with precision between +10°and -10°will be qualified. If we define error limitation as 3 times of mean square error, attitude precision should be in±15°to meet requirement. As a result, the attitude precision measured by digital close-range photogrammetry workstation is feasible.2) The precisions are almost the same and can meet requirement with attitude measure using 800M pixel single-lens reflex camera and 1300M pixel digital camera, which are all±8°. However, wider effective rock mass structural surface can be capture by using 800M single-lens reflex digital camera. Moreover, comparing with 800M SLF digital camera, image distortion is bigger and effective image region is small, which make work burden increased to acquire and process more image pairs.3) To verify the precision of interpretation by digital close-range workstation, we interpreted the overlap area between adjacent image pairs respectively. All result meet precision requirement except one group. The data meeting requirement is 95 percent of total interpretation data.8. We studied close-range photogrammetry method using mobile control system, which make data collection at small region rock mass structural surface available. The design scheme and manufacturing process of this mobile control system was presented in this paper, including material selection, shape, size, etc of mobile control system. Meanwhile, the control point and symbol were designed. 9. Control point on mobile control system was measured by using non-prism total station. It was proved feasible by forward intersection checking, which got position precision of 2mm. It was also proved to be fast and easy-operating. During operating, mobile control shelf is photographed to capture images with rock mass structural surface, which is interpreted on digital close-range photogrammetry. Comparing with compass measure, precision was assessed. It shows the attitude precision of small region rock mass structural surface measure by close-range photogrammetry is±5°, comparing with compass measure's±3°. Defining 2 or 3 times of means square error as limitation, the precision between +9°and -9°will be qualified.10.Application analysis is conducted by interpreted fractures information of Jingyu north mountain quarry, including division of dominating fractures groups and stability analyzing with stereographic projection to offer safe grading angle. Analysis shows that the safe dip angle of N-slope is 80°and it is greater than N-slope's actual dip angle 68°, so N-slope is comparatively stable; the safe dip angle of E-slope is 63°and it is less than E-slope's actual dip angle 83°, so E-slope exists potential instability; Analysis shows that it can be used as the basis in practical work and other safe dip angle of designed can be calculated. Accordingly , it offers standard of design to the project of slope strengthening.Above all, this paper concluded domestic and overseas method of rock mass structural surface information fast acquisition. Two types of method were categorized as contact and non-contact. The advantages and disadvantages of different survey method used in this paper, including compass measure, the actual control points laid and mobile control system, were provided. It is recommended to select appropriate control survey method in practical job to meet the requirement of fast construction.
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