Quantitative foundation stability evaluation of urban karst area: Case study of Tangshan, China

Abstract Karst is a potential geological disaster threatening urban construction. However, the existing methods for evaluating the stability of karst foundations are qualitative. This makes it difficult to propose reasonable and practical suggestions for optimal treatment measures in engineering projects. This paper presents a set of quantitative comprehensive evaluation methods to analyze the karst foundations in a residential area of Tangshan, China. Analyses of the karst formation mechanism and development law are undertaken in combination with a numerical simulation to evaluate the stability of the karst foundations of urban high-rise buildings using the results of a field research to determine the model and the parameters for the numerical calculation. The depth of influence of the foundation of an 8-storey building is less than 30 m. Thus, treatment of the building foundation is not required if there is no karst in the range of 30 m under the surface. However, foundation treatment in the karst zone up to 7 m is required for a 26-storey building with a depth of influence of about 60 m in order to meet the requirements of foundation stability. The employment of a combined approach method is proposed, therefore, as it provides a systematic and practical method for the challenge of optimizing the foundation treatment method for urban high-rise structures in karst areas.