藏区高烈度区高速公路不良地质体分析与防治

Analysis and Prevention of Adverse Geological Body in High Seismic Intensity Area of Tibetan Highway

研究目的:川西藏区高速公路所经区域地质条件极其复杂,工程建设极其困难。工程自建设以来,由于对高烈度地震区不良地质体的定性和防治理念上的差异,造成的工程变更规模相当大,甚至造成工程的报废和工期的延误。基于此,本文以在建的雅康高速公路牦牛沟不良地质体为例,对藏区高烈度地震区不良地质体的定性和工程治理方案进行探讨,以期能为今后藏区高速公路或川藏铁路的安全、经济修建提供一定的借鉴。研究结论:(1)高烈度地震区不良地质体的定性应从坡体地形地貌形态的演变、地质构造、地质类比等多方面进行综合推断,互相校核验证;(2)高烈度地震区坡体的稳定度应依据地质条件、地震历史和走访当地居民等进行综合评定;(3)高烈度地震区大型不良地质体的潜在下滑力对安全系数相当敏感,应依据'小震不坏、中震可修、大震不倒'的原则合理选取安全系数;(4)高烈度地震区大型不良地质体的适当清方和有效的截排水工程是坡体治理首要考虑的措施;(5)本研究成果可为藏区高烈度地震区交通工程的建设提供有效的借鉴。

Research purposes： The regional geological condition of Tibetan region in West Sichuan is extremely complex, and the construction is very difficult. Since the construction of the project began, adverse geological body of the high intensity seismic area and the differences in the concept of prevention and control have resulted in a considerable size of the project change, and even caused the project abandonment and the duration delay. Based on this, this paper takes the Maoniugou adverse geological body of Ya＇an - Kangding highway for exemple, discusses the unfavorable geologic bodies qualitative and project management plan of Tibetan high intensity seismic region, to provide a reference for the future safety and economy construction of the Tibetan highway or Sichuan - Tibet railway. Research conclusions： （ 1 ） The qualitative assessment of adverse geological body in high intensity earthquake zone should be inferred and verified from slope landform evolution, geological structure, geological analogy and other aspects. （2） The slope stability of high intensity earthquake zone should be evaluated according to the geological conditions, earthquake history and visits to local residents. （3） The potential sliding force of large adverse geological body in high intensity seismic region is quite sensitive to the safety factor, should reasonably select the safety coefficient according to the principle of ＂ no damage under small earthquake, repairable under moderate earthquake, and no collapse under strong earthquake＂. （4） The proper clearing and effective drainage of large bad geological body project in the high intensity earthquake zone is the priority measures of slope governance. （5） The research results can provide useful reference for the traffic engineering construction of Tibetan area with high seismic intensity.