北京东部平原区工程地质结构分析及不良地质问题探讨

Analysis of engineering geological structure and bad geological problems of construction layer in the east plain area of Beijing

中文关键词: 北京东部平原区  工程建设层  工程地质结构  不良地质问题

英文关键词: the east plain area of Beijing  engineering construction layer  engineering geological structure  bad geological problem

中文摘要:

      建立工程建设层统一的工程地质结构，分析工程建设面临的不良地质问题，有利于减少工程建设的成本和周期，对城镇规划建设和安全运营具有重要意义。本文通过系统研究北京东部平原区 1∶5万环境地质调查资料，划分了工程建设层的工程地质结构并探讨其存在的不良土体分布规律，结合研究区内存在的环境地质问题，提出了科学合理的规划建设建议。研究结果表明:50 m以浅工程建设层主要为全新世—晚更新地层，可划分 8个工程地质层组，第③层的灰色粉质黏土层、第⑤层的“硬黏土”层、第⑥、⑧层的灰色粉质黏土层是反映研究区气候变化特征的重要标志层，第②、③工程地质层组是软土、盐渍土、液化砂土、腐蚀性土等不良土体的赋存层位。工程建设层内还存在活动断裂、地面沉降、地裂缝等环境地质问题，工程建设过程中应考虑避开环境地质问题集中分布地区，不宜规划建设大规模集中居住区和国家重大基础设施。

英文摘要:

      Establishing a comprehensive engineering geological structure for the construction layer and analyz-ing the encountered geotechnical challenges are essential for cost and time reduction in engineering projects, aswell as crucial for urban planning, construction, and safe operation. The engineering geological structure of the con-struction layer in the east plain area of Beijing is classified and analyzed based on a systematic study of 1∶50,000environmental geological survey data. Furthermore, this paper examines the distribution pattern of unfavorable soilwithin the construction layer.The findings indicate that the shallow construction layer, with a thickness of 50 meters,primarily consists of Holocene-late update strata. This layer can be further classified into eight engineering geologi-cal strata. Notably, the third layer is characterized by gray silty clay, the fifth layer is known as "hard clay", and theeighth layer also exhibits gray silty clay. These distinct layers serve as significant indicators reflecting climatechange patterns in the study area. The second and third engineering geological strata are the occurrence strata ofsoft soil, saline soil, liquefied sand soil, corrosive soil and other bad soil. The construction layer is also affected byactive faults, ground subsidence, ground cracks, and other environmental geological issues. It is crucial to avoid ar-eas with concentrated distribution of these problems during the construction process. Therefore, it is not advisable toplan and construct large-scale concentrated residential areas and major national infrastructure projects.