2004 Vol. 10, No. 1

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IMPORTANT SCIENTIFIC AND TECHNOLOGICAL PROBLEMS IN THE FIELD OF GEOLOGICAL HAZARD PREVENTION AND CONTROL—A DISCUSSION
WU Shu-ren, ZHOU Ping-gen, LEI Wei-zhi, MA Jun
2004, 10(1): 1-6.
Abstract (205) PDF (214KB)(9)
Abstract:
This paper brief introduces the procedure of the drafting work of the early-stage study of the medium-and long-term scientific and technological development program in the field of geological hazard prevention and control of the Ministry of Land and Resources,and then on that basis,the key scientific and technical problems,bottle-neck difficult problems and some important scientific research plans for solving these problems are briefly dealt with from three aspects,i.e.the monitoring,early warning and forecasting of geological hazards,the geological hazard risk assessment of geological hazards and land use and the study of key techniques in control of major geological hazards and emergency treatment.
THEORY AND APPROACHES TO THE RISK EVALUATION OF GEOLOGICAL HAZARDS
MA Yin-sheng, ZHANG Ye-cheng, ZHANG Chun-shan, WANG Jin-shan
2004, 10(1): 7-18.
Abstract (260) PDF (410KB)(20)
Abstract:
The study of geological hazard risk is a new research field that has developed recently and drawn more and more attention of the society.In this paper,the present state of research,definition,characteristics and basic constructive elements of geological hazard risk are systematically dealt with,and on that basis the types of geological hazard risk evaluation are determined and the system,indicator system and procedures and approaches of geological hazard risk evaluation are established.
INDICATOR SYSTEM AND TECHNIQUES OF LANDSLIDE MONITORING
ZHOU Ping-gen
2004, 10(1): 19-26.
Abstract (210) PDF (266KB)(14)
Abstract:
The purpose of landslide monitoring is to provide reliable data and a scientific basis for gaining knowledge of and mastering the evolutionary process of landslides,catching the characteristic information of collapses and landslides in time and making a correct analysis,evaluation,prediction and control of landslides.The indicators of landslide monitoring include the macro geological feature indicator,ground displacement indicator,indicator of displacement in borehole,indicators of ground water(pore pressure,ground water table,ground water chemistry),inducing factor indicators(weather,human activity),geophysical indicator and geochemical indicator.The techniques of landslide monitoring include the extensometer of ground fissures,inclinometer in borehole,global position system,and remote sensing and integrated real-time monitoring and warming system.A case study of the Baota landslide monitoring system in the Three Gorges reservoir area of the Yangtze River is introduced in this paper.
DANGER ASSESSMENT OF COLLAPSES,LANDSLIDES AND DEBRIS FLOWS OF GEOLOGICAL HAZARDS IN CHINA
ZHANG Chun-shan, ZHANG Ye-cheng, ZHANG Li-hai
2004, 10(1): 27-32.
Abstract (303) PDF (302KB)(17)
Abstract:
The danger level of geological hazards is a comprehensive reflection of the density of occurrence, extent of activity and frequency of occurrence of geological hazards.From this view, this paper discusses the structure of danger of geological hazards and method of its assessment. On that basis, the dangerous assessment and divisions of collapses, landslide and debris flows of geological hazards are made with counties (cities, districts and banners) and provinces (municipalities directly under the Central Government and autonomous regions) as the units, and the dangerous distribution and the law of regional changes of geological hazards are analyzed.
CHARACTERISTICS AND FORMATION MECHANISM OF GEOLOGICAL HAZARDS ALONG THE SECTION FROM NYINGCHI TO BAXOI OF THE SICHUAN-TIBET HIGHWAY
LIAO Qiu-lin, LI Xiao, DONG Yan-hui, LI Shou-ding
2004, 10(1): 33-39.
Abstract (240) PDF (232KB)(15)
Abstract:
Geological hazards along the section from Nyingchi to Baxoi of the Sichuan-Tibet Highway are especially severe and have seriously affected the safe riding along the highway. In order to prevent and reduce disasters effectively, regional geological hazards have been studied in the area on the basis of the field investigations and statistic analysis of available data. The results show the following three prominent characteristics of hazards in the area:in terms of distribution geologic hazards are close-spaced, have many types and are notably divided into sectors; loose Quaternary deposits of complex origin form the main material foundation of geological hazards; intense water-rock interaction and coupling of endogenic and exogenic forces are the important factors for the formation and occurrence of geological hazards in the area. This paper provides a scientific basis for the study of the mechanism of occurrence of the geological hazards in the area and measures for their prevention and control.
THEORETICAL ANALYSIS TO TWO CLASSIC LANDSLIDE PREDICTION MODELS: SAITO'S MODEL AND VOIGHT'S MODEL
WANG Jian-feng
2004, 10(1): 40-50.
Abstract (265) PDF (490KB)(14)
Abstract:
Based on the influence of the aging and strain rate of a sloping soil mass on the strength and deformation of the soil mass, as well as the observations of many landslides cases, it has been demonstrated that the mechanism for formation of most landslides can be explained by the deep creep theory. Before a landslide occurs, the creep rate of a soil mass increases with an increase of the factors responsible for the landslide. According to this theory, ones can set up an empirical equation between deformation and time for predicting the time of failure of a landslide. Two earlier typical models are the Saito's model and Voight's model. The author has dug out some newly discovered facts hidden in the two models and developed a generalized prediction model, which can be used to forecast a landslide more accurately. Differing from the Saito's graphic solution method, the author has presented a more convenient technique for estimating the parameters in the equations. The presented method allows the data to be fitted with the presented model and expressed in terms of displacement, through non-linear estimation techniques using the SPRESHEET application software, in order to find values of the controlling parameters(A, B, m, tf) suitable to represent the mechanical behavior of a large-scale landslide approaching the failure. A simple case study has confirmed the validity of both the presented generalized model and estimation technique through computing the deformation-time curve and defining the time limit or failure time value.
GRAY PREDICTION MODEL OF DEFORMATION OF THE HUANGTUPO LANDSLIDE
HE Feng, HU Zhi-jun, WU Shu-ren
2004, 10(1): 51-56.
Abstract (135) PDF (245KB)(7)
Abstract:
The essence of the gray prediction model is to fit the known data sequence with an exponent form to a curve, and then extend the curve to the future in order to predict the unknown data. This paper establishes a GM(1,1) model for prediction of the horizontal displacement of the Huangtupo landslide.Actual application shows that the model is characterized by a high precision and wide applicability.
APPLICATION OF THE FUZZY CLUSTERING ANALYSIS IN THE EVALUATIO NOF REGIONAL CRUSTAL STABILITY IN XI'AN CITY
YANG Jian-jun, XIE Zhen-qian, ZHENG Ning-ping
2004, 10(1): 57-64.
Abstract (167) PDF (294KB)(9)
Abstract:
The authors carried out the evaluation and study of the regional crustal stability and geological hazards in Xi'an City. A wealth of data was gained in geology, geophysical prospecting, surveying and model experiments. According to an analysis of these data and considering such factors as the endogenic and exogenic dynamic geological processes and medium conditions, six principal factors affecting the crustal stability in Xi'an City are selected as a system of the stability evaluation indicators and the fuzzy mathematic method is applied to make a regional crustal stability evaluation. The authors divide the crustal stability in Xi'an City into three grades, sub-unstable, relatively unstable and unstable, and ten areas. On that basis, some guidance suggestions for the urban construction and development plan in Xi'an City are put forward in this paper.
GPS APPLICATION IN LANDSLIDE MONITORING——A CASE STUDY OF THE XIAKOU LANDSLIDE,YA'AN,SICHUAN
GUO Jing-jun, YANG Jiu-long, DING Zhi-gang, ZHOU Ping-gen, ZHU Xiao-guang
2004, 10(1): 65-70.
Abstract (132) PDF (211KB)(10)
Abstract:
A surveying method for landslide monitoring using GPS is introduced. Through the experiment of landslide monitoring with GPS in Xiakou, Ya'an County, Sichuan Province, the authors elucidate the selection of the sites of monitoring stations, lay-out of the monitoring baseline network and method of GPC data processing when GPS monitoring of a landslide is conducted in a mountainous area where the topography is complex and the observation conditions are harsh. The results of the experiment show that GPS landslide monitoring can reach an accuracy of mm scale and can fully meet the demands of landslide monitoring.
THOUGHTS AND BASIC METHODS OF REGIONAL GEOLOGICAL HAZARD RISK ASSESSMENT
CHEN Qi, LI Zhi-yi, SHI Huai-lun
2004, 10(1): 71-80.
Abstract (182) PDF (335KB)(10)
Abstract:
The paper analyzes the regional characteristics of geological hazards and points out that there are regional regularities in the distribution of hazard types, generation conditions and constraints of geological hazards.The paper further points out that the key to the regional geological hazard risk assessment is analyses of the regional geological background, hazard generation regularities and main controlling factors.Finally the paper briefly illustrates the basic thoughts and procedures of regional geological hazard risk assessment.
INTEGRATION OF RS,GIS AND GPS TECHNIQUES FOR GEOLOGICAL HAZARD SURVEY AND EVALUATION
FU Xiao-lin, HUANG Xue-bin, GUO Xi-zhe, XU Kai-xiang, CHENG Wen-ming
2004, 10(1): 81-87.
Abstract (178) PDF (245KB)(11)
Abstract:
This paper briefly describes the application of remote sensing (RS), geopraphic information system (GIS) and global positioning system (GPS) in geological hazard survey and evaluation and the tendency of their integration.The emphasis is put on the discussion of the basic application model in the geological hazard investigation and evaluation and related problems in the context of integration of the "3S" techniques.
AGE OF THE JIAWA FORMATION AND ENVIRONMENTAL EVOLUTION OF LITANG COUNTY,SICHUAN PROVINCE
WANG Shu-bing, Jiang Fu-chu, TIAN Guo-qing, Fu Jian-li, ZHAO Zhi-zhong, XU Qing-hai
2004, 10(1): 88-96,39.
Abstract (151) PDF (352KB)(8)
Abstract:
The Jiawa Formation in the Jiawa Basin, Litang County, Sichuan Province, is a sequence of loose fluvio-lacustrine deposits about 300m deep.According to the magnetostratigraphic, the B M boundary is located at 157.0m depth in the middle part of the section and the Olduvai normal polarity chron is recorded at the bottom.According to Cande and Kent's polarity time scale, it can be inferred that the deposition of the Jiawa Formation stared at about 2.10 Ma BP and ended at about 0.10 Ma BP. On the basis of sporopollen analysis, the vegetation changed from subalpine conifer forest to alpine meadow, and the sedimentary environment varied from fluvial-lacustrine facies to alluvial facies.