9th National Congress on Theoretical and Applied Mechanics, Brussels, 9-10-11 May 2012 Prediction of ground vibrations generated by a falling-weight pavement breaker Mohammad Amin LAK, Stijn FRANC ¸ OIS, Geert DEGRANDE, Geert LOMBAERT Department of Civil Engineering, KU Leuven Kasteelpark Arenberg 40, B-3001 Leuven - Belgium email: amin.lak@bwk.kuleuven.be Abstract— Pavement breaking generates a high level of ground vibration that is potentially damaging to nearby buildings and infrastructures. In this paper, a numerical model for the estimation of the impact load due the blow of a falling-weight pavement breaker is first developed. The esti- mated impact load is in good agreement with the experimen- tal result. Next, the fracturing of the concrete road is investi- gated and the amount of dissipated energy is found to be only a small fraction of the impact energy. The large part of the impact energy is transferred to the soil and causes ground vi- brations. Finally, a non-linear road-soil interaction model is developed and numerically verified. The model accounts for both road-soil separation as well as the inelastic behaviour of the soil. The model is used to predict ground vibrations gen- erated by the operation of a multi-head pavement breaker. Up to 25m from the road, the predicted ground vibrations agree with the experimental results while at large distances the model underestimates the response. Keywords—pavement breaking, ground vibration, falling- weight impact, non-linear road-soil interaction I. I NTRODUCTION P AVEMENT breaking is a common construction activ- ity at the end of service life of rigid pavements and runways. It is performed to prepare the pavement for re- moval or as the first step in a road rehabilitation project. One of the main concerns in this operation is the high level of induced ground vibrations. Ames et al. [1] state that “it is highly improbable that construction equipment, other than pavement breakers, would create sufficient vibrations to approach the archi- tectural damage level.” A peak particle velocity (PPV) of 5mm/s has been considered as the lower limit of archi- tectural damage. Hendriks [2] remarks that pile driving, pavement breaking, blasting, and demolition of structures are among the human activities that generate the highest level of vibration. He also suggests that these operations are potentially damaging to buildings at distances less than 7.5 m from the source. Experimental studies on ground vibrations due to pave- ment breaking are limited while theoretical studies are not found in the literature. The prediction of vibration lev- els due to planned pavement breaking projects can there- fore only be done empirically. This lack of information results in fear for architectural/structural damage and con- sequently a limited use of pavement breakers near resi- dential areas, buried pipelines, and surface installations. In densely populated regions like Belgium, this limitation can be a major drawback. Therefore in the frame of the IWT-project VIS-CO 060884, ‘Vibration controlled stabi- lization of concrete slabs for durable asphalt overlaying with crack prevention membrane’, a numerical model for the prediction of ground vibrations due to the operation of pavement breakers is developed and experimentally vali- dated. This paper presents a study that leads to the devel- opment of such a numerical model. An experiment for model validation has been performed along the N9 road in Waarschoot, Belgium [3] using a multi-head pavement breaker (MHB) as shown in figure 1. In this measurement, ground vibrations are measured dur- ing eight individual impacts of the MHB at four points of a single slab of the road. During these impacts, the accel- erations of the drop hammers, the slab, and the free field - from 5 m up to 105 m from the road - are measured. These results are used herein to validate the models for the es- timation of the impact load and the prediction of ground vibration. Fig. 1. Multi-head pavement breaker used for fracturing of the concrete roads. The outline of this paper is as follows. Section II deals with the prediction of the impact load due to the operation of the MHB. First, a simple model for the prediction of the impact load is developed. Then, the specifications of the MHB, properties of the concrete slabs, and dynamic characteristics of the site soil are presented. Next, the 1