How do you measure and control shrinkage in your soil projects?

1 What is shrinkage limit?

Shrinkage limit is the water content at which soil stops shrinking when it dries. It is also the lowest water content at which soil can be remolded without changing its volume. Shrinkage limit depends on the type, texture, and structure of soil. It is one of the four Atterberg limits that describe the consistency and behavior of fine-grained soils.

2 How to measure shrinkage limit?

In order to measure shrinkage limit, you will need a shrinkage dish, a mercury cup, a drying oven, a balance, and a spatula. Additionally, you will need to gather a representative sample of soil that has been pulverized and passed through a 425-micron sieve. The steps for measuring shrinkage limit are as follows: fill the shrinkage dish with soil and level it with the spatula; weigh the dish and soil and record the mass as M1; place the dish on the mercury cup and press it down until the mercury covers the rim of the dish; weigh the dish, soil, and mercury and record the mass as M2; remove the dish from the mercury cup and dry it in the oven at 105°C for 24 hours; weigh the dish and dry soil and record the mass as M3; calculate the shrinkage limit using this formula: [(M2 - M3) / (M1 - M3)] x 100%.

3 How to control shrinkage in soil projects?

To control shrinkage in soil projects, you should consider soil selection, moisture content, compaction, drainage, and protection. Coarse-grained soils or stabilized soils with additives like lime or cement are good choices for low shrinkage potential. It is important to maintain the moisture content of soil within the optimum range for compaction and avoid over-wetting or over-drying. Compacting the soil to the required density and uniformity using appropriate equipment and methods is also necessary. Additionally, providing adequate drainage to prevent water accumulation and saturation of soil is essential. Lastly, covering the soil with geotextiles, mulches, or vegetation can reduce evaporation and erosion.

4 What are the benefits of controlling shrinkage in soil projects?

Controlling shrinkage in soil projects can bring a number of advantages, from increasing the bearing capacity and settlement resistance of soil to decreasing the risk of cracking, heaving, or subsidence of structures. In addition, it can also improve the durability and performance of pavements and other surfaces, as well as save time and money by avoiding repairs and maintenance.

5 What are the challenges of controlling shrinkage in soil projects?

Controlling shrinkage in soil projects can present some difficulties, such as obtaining accurate and representative samples of soil for testing and analysis, measuring and monitoring the moisture content and volume change of soil in the field, and adapting to the variations in soil properties and environmental conditions. To ensure successful implementation, it is important to follow the best practices and standards for soil engineering and construction.

6 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?