Xining

Collaborating Authors

The Characters of Freeze-Thaw Deformation and the Treatment Technics of Road Slopes in Plateau and Mountain Area

Xu, Shuanhai (Xi’an University of Technology, Xi’an Research Institute of China Coal Technology & Engineering Group Xi’an) | Li, Ning (Xi’an University of Technology) | Cao, Zubao (Xi’an Research Institute of China Coal Technology & Engineering Group) | Liu, Dan (Zhengzhou University)

OnePetroJune, 2013

Abstract According to the analysis, there are five types of deformation failure of the slopes along the road which are shallow freeze-thaw creeping of gravel soil slopes in plateau meadow area, cracking of soft rock high slopes by weathering and freeze-thaw cycling, freeze-thaw slump along the planes of consequent rock slopes, freeze-thaw collapse of big colluvial gravel slopes and freeze-thaw slide along basal rock of residual gravel soil slopes. Grassing, water draining, SNS flexible protection net, concrete insert repair, anchored retaining wall or concrete pier, root pile and anti-sliding pile are selected to treat these deformation failures based on different situation. 1 Introduction There is about 200 km distance of Xining-Jiuzhi class II road,which connects Qinghai and Sichuan province, is in a typical alpine environment and it passes through five mountains higher than 4000 meters. This complicated-geological-condition road has several high slopes and ancient landslides. There are many deformation failures, collapses and landslides occur every year along this road because of the rebuilding, freeze-thaw cycling and weathering. 2 Environmental Geological Conditions Along This Road 2.1 Climatic conditions The weather along this road belongs to plateau mountain climate which is dry, cold, windy and hypoxic. The average temperature is 3.4° and the extreme minimum temperature is -36.2° while the day temperature difference is 16°. The amount of precipitation is 400~500mm which concentrates in from July to September. 2.2 Topography and geomorphology Along this road, there are four geomorphic unitswhich are alpine mountain landscape, alpine mountain basin landscape, alpine deep valley landform and alpine alluvial plain landscape. The altitude of this area is between 3100m and 4000 m. Both south and north sides of this area are higher than the middle which appears like a valley between two mountains. The altitude difference is about 500 m. Most of the alpine deep valleys areV type while U type valleys are rare. There are alluvial flat and first terrace in the bottom of the valleys. Meadows spread over the high terraces and plateau hills.

OnePetro

ISRM

ISRM-SINOROCK-2013-122

ISRM SINOROCK 2013

Calculation Method, conglomerate, deposit, drainage system, freeze-thaw deformation, geological disaster, gravel soil slope, high slope, lithology, mudstone, plane, Reservoir Characterization, residual gravel soil slope, rock slope, sectional sketch, soil slope, stability, structural geology

Country:

Asia > China > Sichuan (0.24)
Asia > China > Qinghai > Xining (0.24)

Geologic Time: Phanerozoic > Cenozoic > Quaternary (0.47)

Industry:

Transportation > Ground > Road (0.57)
Automobiles & Trucks (0.57)

SPE Disciplines: Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (0.51)

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How to Determine the Gas Pipeline Pigging Cycle

Li, Daquan | Ai, Muyang (Pipeline Science & Technology Research Center of CNPC) | Zhang, Peng (Southwest Petroleum Inst.) | Miao, Qing (Pipeline Science & Technology Research Center of CNPC) | Wang, Yubin (Pipeline Science & Technology Research Center of CNPC)

OnePetroNovember, 2011

Abstract Many gas pipeline companies in China is always puzzled by the problem that how to determine the gas pipeline pigging cycle. They are often in a dilemma. On the one hand, If the pipeline pigging work is done timely, the efficiency of pipeline can be improved and the economic benefit can be increased. Except that, all kinds of impurities, liquid and dirt in the pipeline are removed timely, and some pipeline accidents such as ice blocks, corrosion of pipes can be prevented. On the other hand, In order to ensure the pipeline pigging safety and effectiveness, the pipeline operating pressure is reduced than normal. Pipeline flow rate will be greatly affected. And in the process of pipeline pigging operations may also cause the pipe is worn, or even cause pipeline rupture accident. Therefore, if a reasonable pipeline pigging cycle will be determined, the security, economic, social impact and other factors must be considered. Basing on the analysis of relevant laws and regulations or standards, and analyzing the influence of gas supply is can be accepted or not when the pipeline is pigging, except that, including calculated the efficiency of pipeline and condensing liquid volume, some technical methods which are used to determine the pipeline pigging cycle have been discussed. And the application of these methods in the SeBei-XiNing-Lanzhou Gas Transmission Pipeline in China is introduced. It provides reference for the Chinese gas pipeline companies to determine pipeline pigging cycle. 1. Introduction The pipeline pigging operation has been done timely, the pipeline transportation efficiency will be improved and the economic benefit of Pipeline Operation Company will be increased too. Meanwhile, a variety of impurities, water or dirt liquid which are accumulated in the pipeline have been removed timely, that is propitious to prevent pipe corrosion and natural gas hydrate or other accidents. Since the pipeline pigging operations can bring so much benefit. Is the higher pigging operation frequency, the better? Certainly, it is not the case. On the other hand, it has a great influence on the process of pipeline production when the pipeline pigging operation has been done. For example, In order to ensure the pigging effectiveness, it is necessary to control the pig's speed in pigging process, so the pipeline operating pressure should be reduced in pigging process. Therefore, operating parameters and pipeline transmission capacity will change. Furthermore, Pigging operation itself may cause damage to the pipeline system, if the pigging operation process is improper, easily lead to pig is stuck, and pipeline is plugged or even cause pipeline rupture accident. Therefore, how to determine the pipeline pigging cycle reasonably is a question which must be answered before the pipeline system pigging operation has been done. The comprehensive analysis approach of many technical indicators to determine the gas pipeline pigging cycle will be introduced as following. It can be used to guide that the pipeline pigging operation timing is determined. 2. Pipeline Pigging Operation Cycle Determined Methods In the pipeline operation process, there are some water, impurities, corrosion products and other dirt liquids maybe will gradually increasing in the pipeline with the increase of time. Accordingly, gas pipeline operating parameters will change too. Analyzing the changed situation of pipeline operating parameters, whether the transmission efficiency of gas pipeline is meeting the needs of transportation project has been judged.

OnePetro

doi: 10.2523/IPTC-15180-MS

IPTC

IPTC-15180-MS

International Petroleum Technology Conference