青藏高原东南三江流域滑坡灾害发育特征

青藏高原东南三江流域横跨青藏高原东南的高山峡谷区与藏北高原区,地形地貌与气候特征差异大,新构造运动与地震活动强烈,致使该区地质环境脆弱、地质灾害频发、灾害链特征显著,对区内人民生命财产和工程建设的安全、重要基础设施的正常运营构成了严重威胁。本文在利用遥感解译确定青藏高原东南三江流域滑坡灾害空间分布的基础上,探讨滑坡灾害的发育规律及其主要影响因素。 利用GoogeEarth影像结合现场调查进行滑坡灾害的遥感解译,得到滑坡灾害类型及其空间分布;采用分辨率为90m的SRTM数字高程模型（DEM）进行地形地貌特征分析,得到研究区海拔高程、地形坡度、坡向、相对高差栅格图层;以1:50万地质图的地层岩性为基础进行岩组划分并栅格化形成地层岩组栅格图层,以1:50万地质图中的主要断层为基础并与1:150万青藏高原及邻区大地构造图中的主要断裂进行整编后进行缓冲区分析形成距主要断裂的距离图层;根据1:150万青藏高原及邻区大地构造图获得研究区大地构造单元图层。对上述栅格图层分别进行分带、分类后与滑坡灾害空间分布图层进行叠加分析,以滑坡所占面积的百分比为依据绘制直方图,从而得到研究区滑坡灾害的主要发育特征。 在面积为46.2万km2的青藏高原东南三江流域范围内,累计解译面积不小于0.001km2的滑坡灾害60315处,包括滑坡体、崩塌堆积体和变形体3类;以滑坡体为主,占总数的97.73%。滑坡灾害空间分布具有沿深切峡谷成带分布,沿部分断裂构造,如巴塘断裂、维西-乔后断裂、苏哇龙-雄松断裂的拉哇-昌波段等密集分布的特点。从滑坡所占面积的百分比直方图可以看出,滑坡灾害多发育在坡度20~30°、高程小于4000m、相对高差超过1000m的斜坡内。在18类地层岩组中,碎屑岩、板岩夹灰岩组合、泥页岩与粉砂岩组、蛇绿混杂岩、板岩与千枚岩岩组、火山岩等5类为滑坡灾害发育的明显优势岩组。在25个大地构造单元中,金沙江蛇绿混杂岩、中咱碳酸盐台地、那曲-洛隆弧前盆地、保山陆表海盆地、盐源-丽江陆缘裂谷盆地、北澜沧江蛇绿混杂岩、甘孜-理塘蛇绿混杂岩等7个为滑坡灾害明显优势发育的构造单元。尽管距主要断裂距离、坡向对滑坡灾害发育有一定影响,但不显著。 由此可见,青藏高原东南三江流域滑坡灾害发育,影响滑坡灾害发育的地形地貌与地质因素主要为地形坡度、高程、相对高差、地层岩组及大地构造单元,距主要断裂的距离、坡向的影响不显著。     

DF7G型青藏铁路调车机车的研制与运用

以国家铁路用DF7G型调车机车为基础,重点研究了机车各系统、机组和部件适应青藏高原地区特殊的地理和自然条件的技术改进措施,完成了青藏铁路调车机车的设计和制造。运用实践表明,青藏铁路调车机车的系统集成设计合理,采用的各项技术措施是有效的。     

DF7G型青藏铁路调车机车电气系统研究

通过对DF7G型青藏铁路调车机车的电气系统的研究,分析了青藏铁路独特的地理环境及气候条件对机车电气系统的影响,并有针对性地提出了具体的解决措施,指导电气系统的设计开发与试验。     

青藏铁路内燃机车选用油品的建议

通过对青藏铁路内燃机车的使用环境分析,提出了适用于内燃机车所使用燃油、机油的建议。     

对陕北黄土高塬水土流失治理的浅见

陕北黄土高塬水土流失严重。为了彻底解决水土流失和黄河泥沙问题 ,特提出水土保持措施如下 :生物措施 ,工程措施和本区人口高度城市化     

Hydrothermal processes of Alpine Tundra Lakes, Beiluhe Basin, Qinghai-Tibet Plateau

Most of the alpine tundra lakes, of average size 8,500 m², are widely spread in the Beiluhe Basin on the Qing-Tibet Plateau, where ice-rich permafrost exists. Approximately 70% of the lakes are elliptical in shape and 15% are elongated. About 80% of the lakes are unfrozen to the bottom throughout the year while a larger portion of it, about 60%, may be underlain by taliks that penetrate permafrost. The BLH-A Lake, a representative lake with 2-m deep water in the region, has been observed for about four years (from 2006 to 2009). Ice starts to cover on the lake-surface after mid-October, and its thickness increases to 60 to 70 cm by the end of cold season. The ice cover then starts to melt in later April and melts completely around mid-May. The lake-surface temperatures change sinusoidally with the air temperatures, but lagging about half a month. The water warms with the increase of the water depth, and the maximum annual temperature appears at depth of 1.5 m with a value of 14.3 °C on July 30, 2007. The lake-bottom temperatures are not isothermal at different depths for most time of a year. It may be related to the variable climate, little snow, and intensive solar radiation. The mean annual lake-bottom temperatures are about 5.5 °C in the deep pool with 2 m deep water and 4.3 °C in the shallow nearshore zone with 1 m deep water. The warm lake-bottom causes considerable disturbance to the permafrost. Surveyed data show that there is no permafrost under the lake when the mean annual lake-bottom temperature is over 5 °C.     

Characteristics of roadbed settlement in embankment-bridge transition section along the Qinghai-Tibet Railway in permafrost regions

The Qinghai-Tibet Railway (QTR) project was finished on July 1, 2006, and has served for over 3 years. Judging from the present situation, the roadbed is stable and train speed in permafrost regions achieves 100 km/h as expected during the designing. However, as half part of the roadbed was constructed over the permafrost characterized by high ground temperature and high ice content, slight changes of the permafrost might lead to roadbed problems, of which the settlement in embankment-bridge transition section is an obvious and special one. Investigated results of 164 bridges and accounting to 656 positions from the Xidatan Basin to the Chiqu Valley along the QTR in 2009 showed that the settlement was influenced by factors including bridge orientation, embankment slope direction, embankment height, ground temperature, ground ice content of permafrost and local subgrade soil type. For the average value of the settlement, it was greater at the northern end of a bridge than that at the southern end, and was greater in sunny-slope than that in shady-slope. It was greater in high ice permafrost regions than that in low ice regions, and was greater in high-temperature permafrost regions than that in low-temperature regions. Additionally, it increased logarithmically with the height of the embankment. In regions where the subgrade soils were dominated by silt, silty clay or fine sand, the settlement amount was higher than that in bedrock regions. Correlation analysis results showed that there were good relationships between the settlement and the slope direction, embankment height, ground temperature and ice contents when some of the later items were quantified. The correlation coefficients were 0.234, 0.213, −0.21 and 0.151 respectively, when the factors were quantified.     

The thermal effect of differential solar exposure on embankments along the Qinghai-Tibet Railway

The difference in solar radiation produces a predictable thermal effect on the sunny and shaded slopes of embankments constructed in permafrost regions of the Qinghai-Tibet Highway and Railway, which results in differences in soil temperatures and the permafrost table under the shoulder. From the period 2005 to 2008, a systemic network of 42 sites was established along the Qinghai-Tibet Railway to monitor permafrost conditions and embankment performance. Soil temperatures up to 20 m in depth under the embankment were continuously measured hourly. In this article, we investigate daily mean soil temperatures under embankments for 25 observed sites and the temperature difference under the shoulder for both the sunny and shaded slopes of the embankments. We found significant differences in the thermal effect from the sunny and shaded slopes of the embankments along the Qinghai-Tibet Railway. On the sunny slope of the embankment the cooling process of soils under the shoulder is shorter and the thawing process is longer by 15-30 days than on the shaded slope. The multiyear average temperatures under the shoulder for the sunny slope are higher—0.23-1.58 °C with an average of 0.86 °C—than those for the shaded slope. The temperature differences in winter (DJF) are much larger than those in summer (JJA). The multiyear mean permafrost table under the shoulder for the sunny slope of the embankment is larger than for the shaded slope, ranging from 0.1 to 3 m, with an average of 1.13 m. However, engineering measures can effectively reduce the thermal effect between the sunny and shaded slopes of embankments, resulting in a decreasing temperature difference that ranges from 0.46 to 0.71 °C, with an average of 0.58 °C.     

过渡层对青藏公路沥青路面荷载应力影响分析

针对青藏公路目前超载车辆增多,使用条件恶化的现状,从荷载应力对路面结构影响的角度出发,通过力学计算的方法,对比分析了过渡层对路面结构荷载应力的影响,推荐多年冻土地区典型沥青路面结构组合。     

青藏铁路桥梁防冻胀及防冰凌的技术措施

结合青藏铁路长江源特大桥的施工，从承台和墩身的施工两方面，就高原地区的防冻胀及防冰凌的技术措施进行了介绍，对于常年低温环境的施工作业具有指导意义。