PURPOSES: The purpose of this study is to identify the mechanism of road subsidence caused by damaged water and sewer pipes. METHODS: A series of soil chamber test using damaged water and sewer pipe models were conducted under various conditions. RESULTS : Characteristics of cavity expansion and collapse caused by damaged pipes were affected by the damaged location in the sewer pipe, the head on the water pipe, the distance between the damaged water pipe and outlet, and relative soil density. CONCLUSIONS: Sewer-pipe damage was considered a direct cause of road subsidence, and the cavity expanded discontinuously. When the outlet was located under the damaged water pipe, the cavity expanded in the water pipe’s direction, and collapse occurred above the pipe. However, when the outlet was located atop the damaged water pipe, the cavity expanded toward the outlet direction and resulted in a subsidence. Cavity expansion speed was affected by various conditions, such as the pipe’s water head, outlet position, distance between the damaged water pipe and outlet, and relative soil density. However, the cavity expansion shape did not affect factors, except for outlet position.

To evaluate the effect of Jingansikpungtang water extract on cultured mouse spinal sensory neuron which was inhibited by glucose oxidase(GO)-induced cytotoxicity, NR assay and TBARS assay for lipid peroxidation were carried out after the cultured mouse spinal sensory neuron were pre-incubated with various concentrations of Jingansikpungtang water extract for 3 hours prior to exposure of GO. GO, a oxygen radical, decreased the survival rate of the cultured mouse spinal sensory neuron cells on NR assay. Jingansikpungtang water extract have efficacy of decreasing lipid peroxidation increasing by GO in cultured mouse spinal sensory neuron. From above the results, it is concluded that Jingansikpungtang has marked efficacy as a treatment for the damages caused in the GO-mediated oxidative process..