【摘要】 昆明市区坐落在昆明晚新生代断陷盆地内,广泛发育第四纪松散沉积层,以湖沼相粉砂和粘土为主,夹多层淤泥、泥炭及褐煤层。近年来市区发生了大规模的地面沉降现象,沉降范围日益扩大,沉降速率逐年加剧,新的沉降中心不断产生,小板桥、渔户村、大塘子和严家山等4个漏斗形沉降区已逐渐连成一体,构成最严重的沉降区域,其中前两个沉降区形成了总面积约300km2的沉降带。截至1998年小板桥沉降中心的累计沉降量达236 2mm以上,平均沉降速率约20 0mm a,近期高达31 1mm a;河尾村沉降中心近几年下沉速率也达25 1mm a。文章依据1987～1998年期间市区地面沉降的4期水准测量数据,结合区内地质及水文工程地质条件,系统分析地面沉降的空间分布和时程演化特征及其与各制约因素的关系。认为除起因于第四纪松散及半固结土层的自重压密尤其是粘性土、泥炭及褐煤层的压密固结和活动构造的差异性断块升降外,集中超采浅层孔隙水、深层基岩地下(热)水导致的水位持续降低和水位降落漏斗不断扩大及其复合叠加作用,使第四系释水固结,是地面沉降的主要诱发因素。因而,应从地下(热)水开采的合理布局及市政规划入手,采取有针对性的综合防治措施,建立完善的监测网络体系和灾害预警系统,及时开展和加强地面沉降各致害因素的定量评价和系统研?更多还原

【Abstract】 Kunming City lies in the northern section of Kunming late Cenozoic tectonic fallen basin and along the north and northeast shore of Dianchi Lake, and is widely piled up Quaternary loose deposits,which is mainly composed of lake deposits including silly sand and clayey soil layers,carried several layers of silt,peat and lignite.The land subsidence occurred fistly to a certain area in the eastern urban districts in the early 1980s,and up to the latest few years there are four land subsidence zones in shape of funnel in the most gravely occurring central areas of Kunming City,namely Xiaobanqiao zone,Yuhucun zone,Datangzi zone and Yanjiashan zone separately,which are going to be linked together.The former two zones have come into being an area about 180?km~2,the average subsidence rate was about to 200mm/a,the maximum subsidence rate was up to 31.1?mm/a.Being one of the most serious subsidence centers,the cummlative subsidence value of Xiaobanqiao added up to more than 236.2 millimeter during the period from 1987 to 1998 year,and the average subsidence rate of the Heweicun subsidence center was also up to 25.1?mm/a recently.The land subsidence aggravated rapidly,subsidence range enlarged and subsidence velocity accelerated gradually presently.Meanwhile,there appears some new subsidence centers continually.The serious ladn subsidence has damaged buildings,lines and some other constructions,and becomes one of the most important potential geological hazards to the social and economic sustainable development of Kunming City.It is necessary to study on its spreading characteristics and forming mechanism thoroughly.\;Based on the observational level data form precise leveling survey of kunming City area form 1987 to 1998 year,through combining the geological,hydrogeological and engineering geological conditions and analysing the distribution and evolutive rule of land subsidence in Kunming City area and its relations to several dominative factors,it is found that,besides the neotectonic movement being the characteristics of vary extent of ascend and descend,and the sedimentary compress and consolidation of the widely loosen and semi-consolidated Quaternary strata especially the silt,peat and lignite layers whose physical mechanical properties are indirectly relative to the land subsidence,overwi thdrawing deep groundwater and geothermal water and long-playing,which lead to the hydrological conditions change and the water level drop quickly and the depression cone of groundwater table expand rapidly and their interactions,are the vital factor to lead the occurence of land subsidence.In order to control and slower the accelerate of land subsidence and reduce its negative effects on the sustainable development of Kunming City,starting with the reasonable exploitation of groundwater and geothermal water and city planning,adopting the comprehensive countermeasures,constructing the highly precise monitoring system and the hazards information forecasting and warning system,carrying out and strengthening the systematic study on the quantitative evaluation for the causal factors’s respective contribution and reciprocity to the land subsidence,and so on,should be put in practice immediately.更多还原