Soil moisture sensors are important for testing soil strength and stability. Researchers studied how different factors affect the accuracy of these sensors. They tested soil samples in the lab and field using a method called time-domain reflectometry. They found that moisture content and dry density greatly impact soil properties. By developing a calculation model, they accurately measured moisture content in subgrade slopes. The model showed that moisture and temperature affect soil properties, with a high accuracy rate. After six months, the soil dried out and settled, confirming the effectiveness of the monitoring method.