Unlike the rare sightings of large

Unlike the rare sightings of large structures in the ancient world,today, like civilization and commerce,they can be seen in all corners of the world. Bridges span rivers andgorges, while roads wind through snowy peaks or tunnel through the mountains in order to connect people to one another. High-rise buildings accommodate the needs of people in densely populated areas.The fate of these structures depends heavily on geotechnical engineers, whose foundation allow bridges and high-rise buildings to stand firm, whose sound judgment makes mountain roads safe even in bad weather', and whose precise analysis ensures the safety of tunnels. The soil and groundwater'pollution has become more and more commonplace in today's highly industrial environment. It is absolutely necessary for the engineer to have a deep understanding of their construction materials'—the on-site soil and rock conditions. Unlike the man-made materials' of steel and concrete,it is much more difficult to grasp the characteristics of natural materials, since soil and rock conditions vary greatly all around the world. Thus, a geotechnical engineer's priority must be to understand the subtle similarities and differences in soil and rock properties, evaluate the engineering properties of the soil and rock on the site, and determine the suitable design and construction method. The uncertainties of natural elements and different geological properties pose quite a challenge to geotechnical engineers everywhere.