Karst Development Mechanism and Site Stability of Engineering Construction Site Based on Comprehensive Investigation Analysis

In order to ensure the quality and safety of project construction, of which a high-rise building project in Baiyun District of Guangzhou City, located in Guanghua compound syncline basin with strong karst development, based on the methods of geological drilling, literature research, induction and statistics, this paper systematically identifies the landform, stratum lithology, structure and hydrogeological characteristics, the karst development characteristics and control factors were analyzed , and the influence of drilling density and depth on the karst cave rate was discussed, which revealing the karst development mechanism. The stability of karst foundation Qualitative evaluation was carried out. The results show that there are five main controlling factors for karst development in the site, including the topography of overburden layer with strong permeability soil and rock surface contact, limestone combination with seepage channel formed by joint fissure with weak interface, uneven shallow and deep groundwater conditions, crisscross fold fissure and dominant geological structural plane, and deep karst cave caused by neotectonic movement. Erosion is the key factor to promote karst development. Based on the analysis of detailed investigation (karst rate 28.2%) and advanced drilling investigation (karst rate 29.4%), the karst development grade of No.2 site is medium. The karst rate increases with the increase of drilling depth, and the plane development is extremely uneven. The karst foundation is generally in a stable state in the natural state, and the site is suitable for high-rise building projects.