Development, Laboratory and Field Testings of a Bolling Probe for Measuring Stress in Soil

In this study, a cylindrical Bolling probe was developed and evaluated for measuring stress in soil under tire traffic. The probe consists of a silicon rubber head for sensing the soil stress, a PVC tube for transferring the liquid pressure, a digital pressure sensor and a syringe for filling the probe with water and adjusting the initial inclusion pressure. A tank with pressurized air was used for laboratory testing of the probe. The probe head was put into the tank and with sealing the slits, the probe was tested at four initial inclusion pressures of 25, 50, 75 and 100 kPa. The relationship between Bolling and air pressures was investigated. The results showed perfectly linear relationships between the air and Bolling pressures at different initial inclusion pressures. The difference between the Bolling pressure and initial inclusion pressure versus air pressure slightly (