Research on Comprehensive Survey Method of Expressway Crossing Anqiu-Juxian Active Fault.

The highway project from Weifang to Qingdao and its connection line, pass through the active Anqiu-Juxian fault zone. To ascertain the precise distribution, tectonic characteristics, and activity of the Anqiu-Juxian fault within the area of the project, the regional geological structures was firstly studied. It was initially deduced that the Anqiu-Juxian Fault passes through the project in the vicinity of Caocun, which served as the foundation for accurate fault positioning and activity identification. Secondly, through remote sensing, field geological investigation and mapping, the micro-geomorphology and outcrop features of distribution of the fault were discussed. Through seismic geophysical survey on the shallow strata, the distribution pattern of the fault inside the strata were conducted. Through drilling exploration, specific distribution features and activity of the fault were revealed and confirmed. Finally, further analysis of the fault's activity period was conducted by referencing to C14 dating and optically stimulated luminescence dating results from projects nearby. The research results show that, the eastern and western branches of the Anqiu-Juxian fault intersect with the highway project in the vicinity of K24 + 900 and K23 + 550 respectively. The fault's activity period dates back to the Late Pleistocene and Holocene epochs of the Quaternary period, and the F1 and F2 faults on either side are pre-Quaternary faults. After comprehensive analysis and deliberation, it has been established that the eastern and western branches of the Anqiu-Juxian fault show relatively stronger activity within the project area, posing significant influence on the proposed highway. While the activity of the F1 and F2 faults is relatively weaker, exerting less impact on the proposed highway. In accordance with the research results, the new highway adopts general subgrade to traverse distribution zone of the fault. [ABSTRACT FROM AUTHOR]