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This dissertation, Development and Applications of a Drilling Process Monitoring System for Pneumatic Drills by 菅原純, Jun, Sugawara, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled DEVELOPMENT AND APPLICATIONS OF A DRILLING PROCESS MONITORING SYSTEM FOR PNEUMATIC DRILLS submitted by SUGAWARAJUN for the degree of Doctor of Philosophy at the University of Hong Kong in M y 2002 Drilling is undoubtedly one of the most common and important works in geotechnical engineering. However, monitoring and recording of drilling works are usually carried out manually by contractors in the current onshore engineering practice. This study aims at developing a new in-situ device and investigating its applications in the field of drilling and geotechnical characterization of weathered rocks. This type of material has not been amenable to other well-established in-situ tools due to the presence of corestones and. boulders in the decomposed matrix. Similar to the black box of an airplane, a new in-situ device named drilling process monitoring system (DPM) developed in this study can automatically and continuously monitor an entire hole drilling process without any negative effect on the drilling. DPM is a portable system that consists of a shaft encoder position sensor, a magnetic rotation sensor, pressure sensors, a hand-held digital strainmeter, and a DPM data acquisition system. Reinforced data acquisition cables are used to transmit the signal from sensors to the DPM data acquisition system. DPM is operated with only one 12-volt battery. DPM has been applied in slope upgrading works in Hong Kong. It is shown from the studies that the real-time monitoring of drilling works by DPM can improve the currently available manually operated recording method and provide useful information. A series of investigation of using pneumatic DTH drilling parameters for characterization of weathered rocks revealed that DPM has a great potential of furthering geotechnical knowledge. The results indicate that identification of boundaries of weathered rocks between soil and rock ranges, and grade II and grade III rocks are attainable with the penetration rate or a new drilling index Pi. For weathered rocks in the soil range, quantitative way of characterization has been established in this study by using the drilling parameters. An empirical equation has been established for estimating the N value from the drilling parameter Pi, which is used in turn to determine the Mohr-Coulomb friction angle based on the work of Schmertmann (1975). Comparison of results obtained from this approach with those from conventional laboratory tests shows reasonably good agreement, suggesting that the Mohr-Coulomb friction angle of weathered granitic rocks can be estimated with the drilling parameters. DOI: 10.5353/th_b3040918 Subjects: Percussion drillingDrilling and boring

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