Authors: Jorge Abraham Díaz-Rodríguez
Addresses: Facultad de Ingeniería, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3000, Coyoacán, 04510, Mexico
Abstract: The field observations in Mexico City during three large-magnitude earthquakes that occurred on 28 July 1957 (Mw = 7.6), 19 September 1985 (Mw = 8.0) and 19 September 2017 (Mw = 7.1), offered several opportunities for observing a singular phenomenon: the sudden subsidence of ground and settlement of buildings. Sudden subsidence is a phenomenon that is far from being understood, and its transcendence is not fully appreciated. This paper aims to provide an insight into the cyclic compression of clayey soils. To understand the sudden subsidence phenomenon, a series of cyclic simple shear tests were performed on subsoil of Mexico City. These test results show that cyclic simple shear tests at constant vertical stresses agree reasonably well with field observations. Cyclic shear stresses deform the soil sample allowing soil particles to move back and forth. During each shear stress cycle, compression follows expansion, producing changes in the clay structure due to the physical sliding and reorientation of particles. These mechanisms are essential factors in the strength development and the compressibility of clayey soils, resulting in a progressive volume change of the soil, and consequently, the subsidence during large-magnitude earthquakes.
Keywords: Mexico City; large-magnitude earthquakes; sudden subsidence; laboratory results.
International Journal of Earthquake and Impact Engineering, 2022 Vol.4 No.1, pp.83 - 98
Received: 15 Jun 2021
Accepted: 23 Nov 2021
Published online: 13 May 2022 *