How can you ensure a structure's safety during soil liquefaction?

1 What is soil liquefaction?

Soil liquefaction happens when the soil particles are rearranged by the seismic waves and the pore water pressure increases, reducing the effective stress and the shear resistance of the soil. The soil behaves like a liquid, flowing and deforming under the weight of the structures above it. This can lead to settlement, tilting, cracking, or even collapse of the structures. Soil liquefaction is more likely to occur in loose, saturated, and sandy soils.

3 How to design a structure for soil liquefaction?

There are two main approaches to design a structure for soil liquefaction: ground improvement and foundation design. Ground improvement aims to increase the density, drainage, or cohesion of the soil, making it more resistant to liquefaction. This can be achieved by methods such as compaction, grouting, vibroflotation, or stone columns. Foundation design aims to reduce the impact of soil liquefaction on the structure, by choosing a suitable type, size, and depth of the foundation. This can be achieved by methods such as piles, caissons, mat foundations, or shallow foundations with tie beams.

4 How to monitor a structure during soil liquefaction?

During an earthquake, it is essential to monitor the performance of the structure and the soil, to detect any signs of distress or failure. This can be done by using sensors, instruments, or visual inspections. Sensors and instruments can measure the acceleration, displacement, strain, or pressure of the structure and the soil, providing real-time data and alerts. Visual inspections can identify any cracks, deformations, or movements of the structure and the soil, providing qualitative information and recommendations.

6 How to prevent soil liquefaction in the future?

The best way to prevent soil liquefaction in the future is to adopt a proactive and resilient approach to structural engineering, considering the possible scenarios and consequences of soil liquefaction. This can be done by using methods such as hazard mapping, risk assessment, design codes, and contingency planning. Hazard mapping can identify the areas that are prone to soil liquefaction, based on historical data and geological conditions. Risk assessment can evaluate the probability and impact of soil liquefaction on the structure and the society, based on the exposure and vulnerability. Design codes can provide guidelines and standards for the design and construction of structures, based on the best practices and lessons learned. Contingency planning can prepare for the response and recovery of the structure and the community, based on the resources and capacities available.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?