Potential of Waste Rice Husk Ash to Reduce Propagation of Ground Vibration from Impact Piling: Characteristics of In-Filled Trenches

Abstract

Impact pilling inevitably generates seismic disturbance to the surroundings that can cause discomfort to occupants in nearby buildings, disturbance to the activities undertaken in the buildings, and possible damage to nearby structures. To reduce the disturbances to occupants and damages to structures, the propagation of the impact pilling induced ground vibration needs to be assessed and controlled. The objectives of this study are to investigate the characteristics of ground vibration induced by impact piling, and assess impact pile induced vibration based on the available standards and evaluate the effectiveness of trench characteristics (i.e., shape of the trench, multiple trenches, infilled trenches) in reducing the propagation of ground vibration. The ground vibrations were measured by using a four-channel seismograph and a six-channel seismograph. The measured ground vibrations induced by the impact piling were compared with local and international standards. A damping layer was introduced by using six different types of trenches: Rectangular open single trench, rectangular open double trench, trapezoidal open single trench, trapezoidal open double trench, a single trench filled with RHA, and a double trench filled with rice husk ash (RHA). It was found that the magnitude and frequency of ground vibration induced by impact piling in hard soil was greater than that of soft soil. When the excavations were carried out in hard soil the magnitude of ground vibration exceeded the permissible values recommended in local and international standards, implying a necessity of having a method to reduce the propagation of ground vibration to far-field. It was found that rectangular open double trench reduced ground vibration by 82.9% in the transverse direction and 78.8% in the vertical direction. Double trench filled with waste rice husk ash reduced ground vibration by 76.3% in a longitudinal direction. This study concludes that in-filled trenches with waste RHA, an agricultural by-product, has the potential to reduce the propagation of ground vibration induced by impact pilling.