In this paper, simulation on real rock fall by discontinuous deformation analysis (DDA) is conducted. In the simulation, the energy loss of rock fall was carefully modelled in response to each different movement feature of rock fall by using absolute parameter. The energy losses of the rock fall were categorized into three types, that is, the loss by friction, the loss caused by collision and the loss by vegetation. The modelling of the energy loss using absolute parameter has been built in the DDA method. So far, to verify the applicability and validity of the proposed DDA, field tests on rock fall and corresponding simulation of the rock fall tests by DDA have been performed. As the results, the simulated results of rock fall velocity and rock fall jumping height agree well with the results from the field tests. By these results, the new technique in which the energy-absorption ability of slope based on vegetation condition and shape of the rock fall is properly considered, has been established as a new method for the disaster prevention of rock fall. In this paper, consideration of collision damping coefficient and the possibility of reproducibility and predictive analysis had been examined.

防灾减灾的基本理念一般是以防为主,防抗救相结合,其基本环节是防灾、减灾、应急、重建及日常管理,然而以防为主的防灾减灾体系有效性的验证是一难题.日本的道路防灾基本体系是围绕危机管理-防灾对策进行的,而点检是日本道路防灾体系的重要环节之一,自1968年开始实施道路防灾点检以来共实施10次点检.本文概述了日本道路防灾点检方法,对点检评价结果和灾害发生情况进行对比分析,验证了以点检为核心的道路防灾体系的有效性.本研究可以为中国道路防灾工作提供参考.

各种边坡灾害中,落石灾害具有发生频率高、突发性、无前兆、不可预见性、易造成人员伤亡等特点.本文结合日本相关规范和研究成果,概述落石防灾的几个关键技术课题,重点论述落石灾害防治时,落石动态预测的经验、定性以及定量评价技术.

China is an earthquake-prone country,and Sichuan,Shaanxi,Gansu,Qinghai,etc.are earthquake prone areas.The occurrence of earthquakes often results in significant loss of life and property,and will also cause long-term secondary geological hazards such as slope landslides.Earthquake disaster prevention should not only be the emergency rescue after the earthquake,but also the prevention and treatment of long-term disaster prevention and mitigation in this kind of earthquake-prone area.Therefore,it is very important to construct a reasonable and effective policy mechanism and technology system for disaster prevention and mitigation.Based on the technology and experience of disaster prevention and mitigation in Japan,this paper systematically discusses the disaster prevention and mitigation of geological disasters in China's earthquake-prone areas,and discusses the construction of disaster prevention and mitigation system suitable for such areas.

This paper examines a new method for evaluating the stability of rock blocks on slopes using a remotely positioned Laser Doppler Vibrometer (LDV). A series of experiments using physical models were conducted to evaluate the validity of this new method. Based on the experimental studies, the applicability of LDV was examined by comparing results with a conventional seismometer measurement. To examine the quantitative correlations between vibration properties and the stability of a rock block, the effects on the vibration properties of the size of the rock block, the initial block position, the slope incline, and the type of ground surface were studied. The experimental results showed that LDV measurements agreed with conventional seismometer measurements. There was also a good correlation between vibration properties and rock-block stability. On the other hand, it was found that for a boulder on tightly compacted ground, the application of block stability assessment by tonometry was difficult when measuring microtremors or sloppy vibration due to nearby vehicle traffic. Furthermore, numerical analysis of the slope model was carried out to examine the validity of the model experiment and application of the suggested technique. The results of the analysis demonstrated that the suggested technique was effective for application to stability monitoring of a block and evaluation of the effect of stability measures.

This paper developed a new simulation technique of real rockfall by the Discontinuous Deformation Analysis (DDA) and by introducing the probabilistic technique. In order to verify the applicability and validity of the simulation technique, field tests on rockfall and corresponding simulations of rockfall tests were performed. The probabilistic simulation was conducted to examine the unevenness of rockfall.

This paper examines a new method of evaluating the stability of a rock slope using a remotely positioned laser Doppler vibrometer (LDV). An experiment program was conducted by using physical models and a numerical analysis was performed to evaluate the new method. The LDV measurements agreed with conventional seismometer measurements. The dominant frequency of the blocks varied with the stability, and dominant frequency and the amplitude varied with the block size. The numerical model was used to examine a concrete block adhered to a concrete base with different contact areas. The dominant frequency of the blocks determined using the numerical model agreed with those obtained from the physical experiments. These results demonstrated the effectiveness of LDV for evaluating the stability of rock slopes.

PreviousNext No AccessProceedings of the 10th SEGJ International Symposium, Kyoto, Japan, 20-22 November 2011A study on evaluating rock slope stability by remotely-positioned Laser Doppler VibrometersAuthors: Hideki SaitoMasaki TsujiYasunori OhtsukaFumiaki UehanOsamu MurataGuichen MaKazuhide SawadaAtsushi YashimaTakahiro FukataHideki Saito Oyo Corporation (),Search for more papers by this authorEmail the author at [email protected], Masaki Tsuji Oyo Corporation,Search for more papers by this author, Yasunori Ohtsuka Oyo Corporation,Search for more papers by this author, Fumiaki Uehan Railway Technical Research Institute,Search for more papers by this author, Osamu Murata Railway Technical Research Institute,Search for more papers by this author, Guichen Ma Gifu University,Search for more papers by this author, Kazuhide Sawada Gifu University,Search for more papers by this author, Atsushi Yashima Gifu University,Search for more papers by this author, and Takahiro Fukata West Japan Railway CompanySearch for more papers by this authorhttps://doi.org/10.1190/segj102011-001.94 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract The authors have been studying on non-contact measurements of vibrations by remotely-positioned Laser Doppler Vibrometers. The purpose of the study is to establish an evaluation method for rock slope stability by measuring vibrations of rocks. In order to find the relationship between mechanical stability and vibration characteristics of rock blocks, a number of physical model experiments have been carried out, in which concrete blocks were bonded to a concrete base by several kinds of adhesives with various bonding areas to simulate rock blocks with various crack conditions. As the results of the concrete model experiments, we found that the mechanical instability resulted in lowering of dominant frequency of resonantly-generated vibration of blocks. The size of the block affects the dominant frequency. If the bonding length is identical, the larger block shows the lower dominant frequency. The mechanical strength of adhesive also affects the results. If the bonding length is identical, the weaker adhesive shows the lower dominant frequency. Quantitative criteria for evaluating stability of rock blocks are still under considerations. Finally, an example of field data is shown from which we can clearly see the differences of vibration characteristics between unstable rock block and stable rock mass. Although the data suggests that the vibration characteristics can be one of the useful measures, a quantitative evaluation of actual rock block stability needs to be developed in further studies. Permalink: https://doi.org/10.1190/segj102011-001.94FiguresReferencesRelatedDetails Proceedings of the 10th SEGJ International Symposium, Kyoto, Japan, 20-22 November 2011ISSN (online):2159-6832Copyright: 2011 Pages: publication data© 2011 Published in electronic format with permission by the Society of Exploration Geophysicists of JapanPublisher:Society of Exploration Geophysicists HistoryPublished Online: 29 Oct 2012 CITATION INFORMATION Hideki Saito, Masaki Tsuji, Yasunori Ohtsuka, Fumiaki Uehan, Osamu Murata, Guichen Ma, Kazuhide Sawada, Atsushi Yashima, and Takahiro Fukata, (2011), "A study on evaluating rock slope stability by remotely-positioned Laser Doppler Vibrometers," SEG Global Meeting Abstracts : 1-4. https://doi.org/10.1190/segj102011-001.94 Plain-Language Summary PDF DownloadLoading ...

In this paper, simulations of real rockfall by discontinuous deformation analysis (DDA) are conducted. In the simulations, the energy losses of rockfall are categorized into three types, i.e. the loss by friction, the loss by collision, and the loss by vegetation. Modeling of the energy loss using absolute parameters is conducted by the DDA method. Moreover, in order to verify the applicability and validity of the proposed DDA, field tests on rockfall and corresponding simulations of rockfall tests by DDA are performed. The simulated results of rockfall velocity and rockfall jumping height agree well with those obtained from the field tests. Therefore, the new technique properly considers the energy-absorption ability of slope based on vegetation condition and shape of the rockfall, and provides a new method for the assessment and preventive design of rockfall.

This study assessed the relevance of numerical modeling with respect to the mechanical properties of specific rock and investigated the applicability of submarine landslide simulation using discontinuous deformation analysis (DDA). To predict the dynamic behavior of submarine landslides, we developed a way to model a jointed rock mass for the evaluation of rock slope instability and an original DDA approach using an energy loss model that incorporates energy loss caused by collision between blocks and seawater resistance as a viscous force. We applied the developed model to estimate the dynamic behavior of actual submarine landslides. The simulations assessed seawater resistance and energy loss due to collision between blocks, reproducing past events and suggesting the behavior of vulnerable slopes. The results demonstrate that the model can clarify the energy loss caused by slope absorbability and seawater resistance, and that the improved DDA is very useful for submarine land analysis.

Differential interferometry using Synthetic Aperture Radar (InSAR) is a powerful technology for detecting surface deformation of ground. In this technique, surface deformation of ground such as ground subsidence, land slide, slope failure, can be analyzed from different phase of micro-wave between two observed data by SAR. The accuracy of measurement is less than plus-and-minus 1 cm. Moreover, it has an advantage that the deformation of the ground surface with respect to time can be investigated from the analytical results. The Advanced Land Observing Satellite, ALOS, has been launched by Japan Aerospace Exploration Agency (JAXA) on January 2006. In order to detect ground subsidence or change caused by mining, overuse of ground water, disaster, and so on, an analytical investigation is applied in this study. Observing result in InSAR can apply to forecast to geographical hazard and environmental reclamation planning

In Wenchuan earthquake occurred on May 12,2008 in China, severe earthquake with magnitude 8.0 hit Wenchuan Xian. The earthquake caused many geological disasters such as rockfalls, slope failures and landslides. Huge number of geo-structures was also damaged by the earthquake. The field inspection was carried out by authors twice three weeks later and about two months after earthquake. In this report, several kinds of disasters near the epicenter were summarized, and damages of geo-structures were analyzed based on the relationship of the geo-structures damage and the ground behaviors. Furthermore, the effects of countermeasures against geological disaster such as slope net, shotcrete, earth anchor and reinforced soil wall are also discussed based on the results of filed inspection. It was found that there is high correlation between the damages of geo-structures and ground behaviors, and countermeasures of slope disasters played an important role for the prevention disaster. Finally, an application example of the surface-wave method was summarized.

The technology of deformation monitoring in open-pit mines has been a crucial job on the mine safety production.In recent years,it is an important direction on studies of the microwave remote sensing to monitor the slope deformation by using synthetic aperture radar interferometry(INSAR) measurement technology.This paper analyzes the technical advantages and the research progress on INSAR technology to monitor the slope deformation;compare the measured data of monitoring Haizhou open-pit mine by traditional technology with the monitoring data of INSAR measure.The result shows the INSAR technology can achieve an effective monitoring on the slope of the large-scale open-pit,which has certain technical advantages and broad prospects.

Aiming at the increasingly serious pollution and ecological damage in mining cites, environmental information urgently are urgently needed to provide basis and decision-making for the economic transition of mining cites. This article describes main environmental problems existing in mining cites, as well as ways of monitoring these major environmental problems, such as the Landsat TM images are used in Land use dynamic monitoring, High Spectrum Images are used in the extracted vegetation monitoring, and the water quality change is monitored by the way of NOAA / AVHRR. Particularly, the effectual way of the Interferometric Synthetic Aperture Radar (InSAR) landslides monitoring is introduced, which is well applied to the opencast mine of Haizhou and Fushun in China with this technology. Differential interferometry using Synthetic Aperture Radar (SAR) is a powerful technology for detecting surface deformation of ground. Surface deformation can be analyzed from different phase of micro-wave between two observed data by SAR. The accuracy of measurement is less than plus-and-minus 1 cm. Achieved research results will provide early warning of environment disasters, rapid & real-time information and interpretation means for the mining cites.

This paper deals with the relevance of numerical modeling with respect to mechanical properties of rock proposed, and discusses the applicability of rock fall simulation by using discontinuous deformation analysis (DDA). In order to foresee collapse of rock slope, numerical method will be extremely useful. However, it will be difficult to simulate collapsed, considering difficulties of rock parameter, such as geology, fracture, fault and laboratory testing into numerical calculation. We present the way to modeling the jointed rock mass to evaluate the rock slope instability, and a simulated result for an actual rock mass collapse are shown. Furthermore, it was discussed that the applicability of rock fall simulation by using DDA for numerical experiments and the investigation of rock fall in the northern part of Japan. In order to predict the behavior of rock fall, the energy loss model considering collision has been built in the original DDA. The energy loss caused by slope absorbability can be clarified in this model. The improved DDA is supposed to be very useful for rock fall analysis and measures design.

Differential interferometry using Synthetic Aperture Radar (SAR) is a powerful technology for detecting surface deformation of ground. In this technique, surface deformation of ground such as ground subsidence, land slide, slope failure, can be analyzed from different phase of micro-wave between two observed data by SAR. The accuracy of measurement is less than plus-and-minus I cm. Moreover, it has an advantage that the deformation of the ground surface with respect to time can be investigated from the analytical results. The Advanced Land Observing Satellite, ALOS, has been launched by Japan Aerospace Exploration Agency (JAXA) on January 2006. ALOS carries synthetic aperture radar, Phased Array type L-band Synthetic Aperture Radar (PALSAR). In order to detect ground subsidence or change caused by natural resources mining, overuse of ground water, disaster, and so on, an analytical investigation is applied in this study. From the result of analyses using data from PALSAR, the location and area of deformed surface is detected and investigated.

本研究では，落石挙動を正確に表現するための解析手法を開発するに当たり，現場実験によって落石挙動を表現するためのエネルギー損失のメカニズムを検討し，落石のエネルギー損失を，摩擦による損失，落石と斜面の衝突による損失および植生による損失の3種類に分類する必要があることを明らかにした．次に，その考察に基づき，当該エネルギー損失をそれぞれ独立なパラメータを用いて表現できるような係数を導入した非質点系の解析手法である不連続変形法を開発し，現場実験に対するシミュレーションを実施し，当該手法の妥当性を検証した．その結果，実際の斜面の地形地質条件，植生条件および落石形状等を考慮に入れて，落石の挙動を正確に求めるシミュレーション手法の構築が可能であることを実証した．