Importance of precipitation on the slowdown of creep behaviour induced by pressure-solution

TL;DR

This study numerically investigates how precipitation influences the slowdown of pressure-solution creep in rocks, revealing different mechanisms at slow and fast precipitation rates.

Contribution

It introduces a calibrated Phase-Field Discrete Element Model to analyze precipitation effects on pressure-solution creep.

Findings

Slow precipitation causes slowdown via solute accumulation.

Fast precipitation causes slowdown via stress reduction.

Model validated against indentation experiments.

Abstract

Pressure-solution is a chemo-mechanical process, involving dissolution at grain/asperity contacts and precipitation away from them. It induces a compaction in time of rocks and sediments. The present study investigates numerically the impact of precipitation on the slowdown of creep behavior induced by pressure-solution. A recently published framework, called the Phase-Field Discrete Element Model, is carefully calibrated against existing indentation experiments and validated for other rate-limiting scenarios. It is shown that when precipitation is relatively slow, the slowdown of pressure-solution is due to a chemical mechanism (accumulation of solute concentration within the pore space), whereas, at fast precipitation, the slowdown is due to a mechanical mechanism (stress reduction at the contact).