| Yunnan Province, which belong to low latitudes plateau and its south slope, is the combination positions of Eurasia's plate and India's plate, complicated geological structure, the geological calamity is various, the geological environment is extremely complicated in China. From the eastern to the western regions of the Yunnan Province, there have been many differences in territorial the earth's crust stabilities , soil body structure and physiognomy involvement; the faultages are very strong activity for the whole province, it is obviously controlling Yunnan Province's basin deposit, physiognomy forms and, water system distributing and earthquake. Within Yunnan province, the earthquake often occur in the regions of Daguan-Mabian, Xiaojiang, Tonghai-Shiping, Zhongdian-Dali, Simao-Laizhou, Tengchong-Gengma Zones, more than 90% strong earthquake , which M 6 grades , concentrately took place in these 6 earthquake zones. According to calculate and appraise the stability of the whole province regional the earth's crust, the region can be divided into 4 stable sections, 2 secondary stable sections and 6 unstable sections. Bad soil body is distribute widely. Regional geological calamity mostly include earthquake, collapsing, landslides, mud-rock flows, ground cracks, karst subsiding, surface subsidence % soil erosion, land desertization and endemic. Among them, soil erosion of the whole province area is 141333.70 km2 in 1999, it accounts for the 36.88% of whole soil land, soil erosion more than third grade is 61351.27 km2. The uncovered rock area occupy 70% in whole province is more then 8470.4 km2, account for 2.21% of territory. Collapse, the landslide, mud-rock flow are endangered seriously. The whole province including Guikun, Chengkun, Kunhe, Guangda and Dongchuan branch about 489 km railways, and around 3000 km county or above county grade highways are endangered by the geological calamity. At present, there are 4 collapse, the landslide, mud-rock flow very strong activity zones-north of Deqin, Mmgyin-Qina-Binchuan, Yuanmou-Dongchuan-Qiaojia-Suijiang-Jinshajiang and its branchs, Yingjiang-lianghe , and 2 collapse , the landslide , mud-rock flow strong activity zones -Gongshan-Yongping-Yuanyang, Yanjin-Zhenxiong, and many moderate, low-grade activity zones.Building international big pathways, regional environmental geologies are effected by natural geological environment and engineering activities. The main environment geological question is: The earth's crust where the faultage and earthquake are active is unstable; collapse , landslide, mud-rock flow and soil erosion ; The underground karst subsides, seepage question; Basic rock expand, expend and compress soil body, the salt deposit corrode out of shape and groundwater's corrodent harm; The soft soil question of basin; The soft rock body, cracked rock and the weathering rock are relatively poor stability; High and cold regional highways and railways' frozen soils freeze and melt calamity problem; The around rock of tunnel are unstable because of the coal seam gas, spring water, underground developed area; Project cutting slopes, constructed abandon soil and reservoir, lake's ecology geological environmental protection issue; Thedangerous shoal of the channel % submerged reef question; The problem of rebuilding channel project and dock etc.; And the problem of unstable ground and groundwater corrosivity during building airport; At the same time, with the international big pathways' implementation and completions of constructions, adjusting the cities and counties' constructions , the crowd occupy changing , the cultivated land distribute changing and the adjustments of structure, will cause local environmental geological issues' outstanding; According to multiple statistical analysis , value calculate and integrated appraise result, in the northwest and southwest of Yunnan, the traffic relatively low density, traffic engineering is relatively weak impact on environment, It is the area where a environme... |
