Stability analysis of slip of a one-body spring-slider model in the presence of thermal pressurization

Jeen-Hwa Wang

Abstract


This study is focused on stability of slip in a one-body spring-slider system, with stiffness k of the slider, in the presence of thermal pressurizationfor two end-member models of thermal pressurization, i.e., the adiabatic-undrained- deformation (AUD) model and slip-on-a-plane (SOP) model. Analytic studies based on the functions of frictional stress, tf, versus slip, d, of the two models show that kcr=|dtf/dd| at d=0 is the critical stiffness of the system. kcr is a finite positive value for the AUD model and infinity for the SOP model. Slip is stable when k>kcr and unstable when k<kcr. Analytic stability conditions of slip from the equations of motions of a one-body spring-slider model with the tf–d function of the ADU model are also those from |dtf/dd| at d=0. Under ADU thermal pressurization, modeled final slip and maximum velocity for k=5 to 31 MPa/m, with kcr=30 MPa/m, both decrease with increasing k. The motions become very weak when k≥kcr, thus being unable to result in unstable motions. The phase portraits of v versus d for k<30 MPa/m show the existence of a non-zero unstable fixed point.

Keywords


Slip stability; One-body spring-slider system; Friction; Thermal pressurization; AUD and SOP models

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References


DOI: https://doi.org/10.4401/ag-5548

Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X