The majority of the 2008 permafrost and cold regions engineering studies in China were associated with the construction and maintenance of high-elevation highways and railways in Southwestern China (Qinghai-Tibet Plateau) and the construction of a 1,030-km, 813mm-diameter, ambienttemperature crude oil pipeline in Northeastern China. Additional research in permafrost science was focused on augmenting and developing basic long-term data collection at established stations in both areas.
Qinghai-Tibet Highway (QTH): The QTH was upgraded during 2003-2007 for hauling the large tonnages of fi ll and construction materials for building the Qinghai-Tibet Railway (QTR). Although the traffi cability has been greatly improved, however, the thaw subsidence resulting from asphaltic pavement continues, the thaw depths have reached more than 10 m beneath the road in some segments. Permafrost temperatures were monitored at more than 100 cross-sections along the QTH. Proposed Qinghai-Tibet Express Highway (QTEH): An express highway (QTEH) has been proposed paralleling the QTH and utilizing the relatively lower relief, but high elevation, naturally occurring engineering corridor from Golmud to Lhasa. A thawed belt has been proposed, however, some designers also are considering alternative routes to avoid congestion and extensive and asymmetrical (old and new lanes) thawing of the permafrost in this relatively narrow engineering corridor.
Qinghai-Kang (Western Sichuan) Highway (QKH): The QKH on the eastern Qinghai-Tibet Plateau has required major maintenance each year because the permafrost subgrade has been thawing. Several stations, with boreholes and automatic data recording, along the route, were established at Huashixia, Zuimatan and Qingshuihe.
Xinjiang-Tibet Highway (XTH): The Tianshuihai Permafrost Station established in 2007, functioned well during the 2008. More than one-year of data on ground temperatures and weather conditions were obtained and some initial analysis has been done by German and Chinese scientists both in Lanzhou, China, and Heidelberg, Germany.
Qingshuihe-Budongquan Highway (QBH): The QBH is a connecting road between the QTH and the QKH. It traverses a signifi cant amount of permafrost. Th e Sino-German Research Team from Heidelberg and Lanzhou worked together on surveys and investigations using geophysical methods. Two more permafrost stations were established at Quma’he and Chumar’he. Field data have been collected for two years. Th ese data generally include ground temperatures and weather data from automatic stations.
Qinghai-Tibet Railway (QTR): The research continued on the verifications of permafrost railbed cooling confi gurations both along the railway and at the experimental stations. To date, the foundation soils have been performing as designed. At some segments, the cooling eff ects have been better than expected, and the permafrost table beneath the railbed has risen into the base of the fi ll.
Muli Coal Mine Railway: During 2007, large-scale development of the Muli Coal Mine in Qinghai was approved, necessitating the building of an 140-km-long coal-transport railway from Reshui to Muli. About 60% of the route is underlain by Drilling permafrost. The permafrost sections are largely located in wetlands on gentle slopes, with high-ice content and warm temperatures of about -1.5 to -0.5 °C. Some mitigative measures such as block-embankments, sometimes strengthened with thermosyphons, and revegetated side protection slopes were adopted for protecting permafrost and ensuring the stability of the railway foundations. The thermal stability of permafrost foundations was monitored, studied and evaluated at six crosssections along the railway. The railway is to be in operation in 2009.
The Qilian Mountains are located on the northeastern edge of the Qinghai-Tibet Plateau. The area is rich in mineral resources, and water resources vital for the downstream economy and social development. The evaluation and exploitation for these resources have advanced the research on permafrost in the mountains. During the 1960s, some major surveys were conducted for the development of the Muli coal mine, with some permafrost data. Surveys on permafrost along the highways during the 2004-2005 period and local railway construction during 2007 also accumulated valuable data on permafrost distribution.
Since 2007, the permafrost studies on the southern slopes in the Qilian Mountains has been revived. The presence of permafrost here is closely related to wetlands, and permafrost is ice-rich. Permafrost conditions along the upper tributaries of the Shu’le River on the northern slopes at the western section of the Qilian Mountains were investigated in 2008. The climate is dry, the surface vegetation is sparse and unlike on the southern slopes, the permafrost is generally ice-poor. Permafrost is warmer compared to that at similar elevations on the southern slopes. Three monitoring sites for ground temperatures and two automatic weather stations were installed to study the permafrost.
Chinese-Russian Unheated Crude Oil Pipeline (CRUCOP): The construction of the 1030-km, 813mm-diameter, unheated (ambient-temperature) crude oil pipeline (CRUCOP) is scheduled to begin in March 2009, and to require about 18 months for completion. The section in China, 953 km, is from Mo’he to Daqing and traverses about 441 km of warm (>-1°C) permafrost. The assessment of the engineering geological conditions, and predictions of frozen foundation soils around the pipeline have been completed. The design of the pipeline construction mode, basically all conventional burial, is closely elaborated with the research results at all phases of survey and design. Environmental concerns and mitigation measures for frost hazards during the construction and operation periods were carefully identifi ed and studied to minimize unnecessary costs to the environments and for construction, maintenance and operational safety. Some results of these studies will be published in a special issue “Pipelines in Permafrost Regions” of the journal Cold Regions Science and Technology.
Mo’he Airport: The other studies include a permafrost survey related to the construction of Mo’he Airport and monitoring of permafrost foundations beneath the runway. This is the fi rst airport in the permafrost regions of China. Although the mean annual air temperature was about -5°C during the past 50 years, the permafrost is warm (>-1°C) and ice-rich. Some excavations for ice-rich permafrost and refilling with coarse blocks were used to ensure the stability of the runway foundation. Several cross-sectional measurements of ground temperatures and deformations of foundation soils were installed in 2007. Some good data have been collected.
Gen’he-Yituli’he Permafrost Station: Eight boreholes were drilled in the Gen’he-Yituli’he area in the middle section of the Da Xing’anling (Hinggan) Mountains in June to July 2008 for measurements on the ground temperatures of various surface coverage conditions in the subarctic taiga forests and wetlands. Two automatic weather stations and soil moisture measurement fi elds were also established for the forested wetlands and shrubcovered wetlands in the Gen’he area. These establishments include the present permafrost station at Gen’he-Yituli’he.
The single borehole about 8 m in depth drilled in the Yituli’he town is only a few meters distance from a former borehole of about 14 m in depth. This damaged and abandoned borehole had a data series from 1981 to 2005. Inactive ice wedges groups were fi rst identified in 1987 and they were re-excavated in 2007 for detailed analysis.
Five boreholes in the Gen’he area are located inside the China Forest Ecological Research Network Station in the Da Xing’anling Mountains, 16 km north of the Gen’he city with a pollution of about 180,000. One borehole was established inside the to-be-abandoned meteorological station in the center of the city. The meteorological station had to be abandoned because of increasing urbanization and its impacts on the representativeness of the collected data. Another borehole was established about 3 km north of the meteorological station, which is in the outskirts of the city. The eight boreholes in the Gen’he areas, two automatic weather stations, and many other setups for forestry studies are aimed at the understanding of the interactions among the boreal ecosystem, permafrost, snow cover, and human activities. In particular, the rapid urbanization has been greatly impacting the permafrost and vegetation in this area.
Other Permafrost Projects Large-scale synchronous of satellite- and airborne and ground measurements of permafrost, vegetation and snow cover were also planned and conducted along the upper and middle tributaries of the Hei’he Watershed in the middle section of the Qilian Mountains. A transect study profi le from the mountain top at elevations of 4,400 m a.s.l. to the control hydrological section at 3,200 m a.s.l. was established for the long-term study at Binggou Creek. The results will be published in a special issue “WATER” on the Hydrological Processes.
Huijun Jin (email@example.com)