露天矿边坡监测技术外文翻译(编辑修改稿)

露天矿边坡监测技术外文翻译(编辑修改稿)内容摘要：

4]. The second step is to establish the project requirements, which follows from the pit design and a risk assessment. The oute of this will state the probability of failure and the variables that will most likely contribute to such failure. The third step will take account of these variables in designing the monitoring system, considering instrumentation and implementing the monitoring system [5]. The fourth step is the actual measurement and recording of field data. Measuring techniques and frequencies, accuracy, precision and personnel responsibilities are very important at this stage. Fortunately, this would have been taken care off during the design of the monitoring system. The fifth and final step is interpretation and reporting of monitoring data. The reporting of results and documenting of events, decisions, design changes and costbenefit analysis plete the monitoring process. Surface Measurement The surface measurement involves some techniques among which are: survey work and tension crack mapping. Survey Network. A survey work consists of target prisms placed on and around areas of anticipated instability on the pit slopes with one or more control points for survey stations. These stations need to be located close enough to the pit crest so that all prisms can be readily seen。 the stations must also be located on pletely stable ground. Electronic total station located at a monitoring station (established inside a small hut) built for such purpose, measures the angles and distances from the survey station to the prisms on a regular basis to establish a history of movement on the slope. Data collected by the total station is transmitted by radio from the pit edge to the survey office where a puter fitted with appropriate software is located. Data e into the puter as survey coordinates of the individual prism targets. Correction for atmospheric variations is made by incorporating data collected by a bined temperature/atmospheric pressure transducer. Changes that have occurred with respect to the original position of the slope monitoring targets are calculated by the software and shown in graphical format. The Geodetic monitoring system (GEOMOS) is a typical survey work for slope monitoring that runs for 24 hours a day. The system is subdivided into three parts: data collection, date transmission, data processing and analysis [1]. Note that the optical mechanical theodolites are nowadays rarely used for slope monitoring, due to their low efficiency and the often significant atmospheric refraction errors in observed angles [5]. A major problem of the survey system of slope monitoring is the error caused by atmospheric factors such as dust and haze. Human error, damage to prism or displacement of the survey station can equally affect measurement accuracy. Errors can also be introduced by instrument or reflector setup inaccuracies. In some locations, prism theft is another concern。 Tension Crack Mapping. The formation of cracks at the top of a slope is an obvious sign of instability. Measurement and monitoring the changes in crack width and direction of crack propagation is required to establish the extent of the unstable area. Existing cracks should be painted or flagged so that new cracks can be easily identified on subsequent inspections. Measurements of tension cracks may be as simple as driving two stakes on either side of the crack and using a survey tape or rod to measure the separations. Another mon method for monitoring movement across tension cracks is with a portable wireline extensometer. The most mon setup is prised of a wire anchored in the unstable portion of the ground, with the monitor and pulley station located on a stable portion of the ground behind the last tension crack. The wire runs over the top of a pulley and is tensioned by a weight suspended from the other end. As the unstable portion of the ground moves away from the pulley stand, the weight will move and the displacements can be recorded either electronically or manually. Long lengths of wire can lead to errors due to sag or to thermal expansion, so readjustments and corrections are often necessary. The length of the extensometer wire should be limited to approximately 60m (197ft) to keep errors due to line sag at a minimum [7]. Most of the extensometers currently in use have a digital readout. Readings can be taken manually by site personnel or can be stored in an electronic data logger and then downloaded to a personal puter. Electronic extensometers can be linked to an alarm system. When reading exceeds a certain preset limit, an alarm can be set off automatically to warn of the potential danger of pit failure. Under normal conditions, this works very well but they can be accidentally triggered。