Sandstone, laterite and soils are main construction materials of the Angkor monuments. Gray to yellowish brown sandstones, which were used commonly in the Angkor monuments, consist of the same minerals and have almost the same chemical composition. However the gray to yellowish brown sandstones can be classified by a non-destructive measurement of magnetic susceptibility. The magnetic susceptibility of the sandstones changed with age reflecting a difference in quarry. The gray to yellowish brown sandstones have been deteriorated by salt weathering, growth of lichens and algae, and a sunbeam etc. This paper reports non-destructive examinations for the gray to yellowish brown sandstones by using rock hardness testers, an ultrasonic tester, a thermal infrared camera, an electromagnetic wave radar and moisture meters.

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Kyushu University is moving to a new campus located in the western part of Fukuoka city. There are many archeological remains such as keyhole shaped mound tombs around the new campus. We have developed an automatic electrical resistivity measuring system named Handy-ARM (Handy Archaeological Resistivity Meter) for archaeological prospections. We carried out electrical resistivity prospecting by Handy-ARM at the keyhole shaped tomb named Shioyoke Kofun in the new campus. After two-dimensional inversion of observed data, we have found that low resistivity anomalies were distributed from 2m to 4m deep of central part of the circular mound and high resistivity anomalies were detected at the slope of the circular mound. We have also developed three-dimensional imaging software using three-dimensional CG (Computer Graphics) to display results of an electrical resistivity survey for an archaeological prospection. It is obviously effective not only for geophysists but also for archaeologists to evaluate survey results by using the three-dimensional imaging program.

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The ancient city wall of Xi'an is the most complete city wall that has survived in China, as well being one of the largest ancient military defensive systems in the world. The wall now stands 12 meters tall, 12-14 meters wide at the top and 15-18 meters thick at the bottom. It covers approximately 14 kilometers in length. It is also one of the most valuable historical structures in the world. However, the wall has a large amount of caves in it. People have caved these caves during wars as bomb shelters. It is considered that total length of caves would be 41 kilometers. These caves, especially caves that exist in the shallow part of the wall, often bring sinking of the top of the wall. To protect the historical heritage, these caves should be fixed as soon as possible. It is important, therefore, to detect nondestructively the distribution of caves. To get the images of caves, we have carried out geophysical survey at the top of the wall using ground-penetrating radar (GPR). As the results we obtain three-dimensional images of caves that exist in the shallow part of the city wall. We have also clarified the relation between cracks on the surface of the ancient city wall and the caves. These results are important information for protecting the historical heritage.

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Use of non-destructive inspection is quite effective to make reasonable plans for both maintenance in existing concrete structures and quality control in new concrete constructions. Therefore, the role of non-destructive inspection to keep safety and reliability of concrete structures is supposed to become greater.
In the chapters related to “Inspection” in standard specifications for concrete structures -2001 “Maintenance” (from chapter 5 to chapter 9) published by Japan Society of Civil Engineers, it is encouraged to use non-destructive inspections in parallel with others methods. Moreover, in chapter 10 (techniques of testing and surveying), classification and summary of non-destructive inspection methods are presented. On the other hand, in “Diagnosis technology for concrete structures [Basic]” published by Japan Concrete Institute, outline of non-destructive inspection for diagnosis of concrete structures is demonstrated. In this way, non-destructive inspection has been especially increased its applications during maintenance of concrete structure.
This paper describes classification of methods, basic principle and characteristics of each method, evaluation indices and targets of non-destructive inspections for diagnosis of concrete structures. At first, Japanese standards and recommendations for non-destructive inspection of concrete are listed. Next, target of evaluation of non-destructive inspection is classified among “quality (strength) of concrete”, “internal defects” and “detection of reinforcing bar location”, then summary of each inspection methods is explained respectively. Inspection methods using digital camera or laser system, robot with sensor are introduced. Finally, future prospect of non-destructive inspection is discussed from the standpoint of better use for concrete structures.

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A hybrid method with genetic algorithms and simulated annealing is proposed to invert surface-wave phase velocity to a 1D S-wave profile. The basic computational flow of the hybrid algorithm is principally based on the genetic algorithm by Yamanaka and Ishida (1995). However, a generation-dependent probability for choosing new models in the crossover operation is introduced in the hybrid method. The probability is defined in a similar manner as the simulated annealing using temperature that should be decreased with increasing generations. In addition to this operation, we used a real-number coding of parameters in the method. I examined the performance of the method in finding optimal S-wave velocities and thicknesses through numerical experiments using synthetic Rayleigh-wave phase velocity for a 4-layers model of deep sedimentary layers. It is concluded that the hybrid method can find an optimal model with less computational efforts than those the conventional genetic algorithm and simulated annealing. These features of the hybrid method can be also recognized in application to actual phase velocity data observed in microtremor explorations in the Kanto basin, Japan.

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