# A State-Dependent Elasto-Plastic Model for Hydrate-Bearing Cemented Sand Considering Damage and Cementation Effects

## TL;DR

This paper introduces a new model to predict the mechanical behavior of sand containing gas hydrates, which can help improve gas extraction and tunnel construction.

## Contribution

A novel state-dependent elasto-plastic model incorporating cementation and damage effects in hydrate-bearing sand is proposed.

## Key findings

- The model accurately replicates soil cementation and deterioration with over 90% compliance to experimental data.
- The model considers damage evolution and hydrate cementation reduction through plastic shear strain.
- The model provides guidance for deep tunnel construction and hydrocarbon extraction.

## Abstract

In order to optimize the efficiency and safety of gas hydrate extraction, it is essential to develop a credible constitutive model for sands containing hydrates. A model incorporating both cementation and damage was constructed to describe the behavior of hydrate-bearing cemented sand. This model is based on the critical state theory and builds upon previous studies. The damage factor Ds is incorporated to consider soil degradation and the reduction in hydrate cementation, as described by plastic shear strain. A computer program was developed to simulate the mechanisms of cementation and damage evolution, as well as the stress-strain curves of hydrate-bearing cemented sand. The results indicate that the model replicates the mechanical behavior of soil cementation and soil deterioration caused by impairment well. By comparing the theoretical curves with the experimental data, the compliance of the model was calculated to be more than 90 percent. The new state-dependent elasto-plastic constitutive model based on cementation and damage of hydrate-bearing cemented sand could provide vital guidance for the construction of deep-buried tunnels, extraction of hydrocarbon compounds, and development of resources.