Design Of Seismic Cone Penetration Testing System

Seismic cone penetration test (SCPT) is a brand new in-situ test in the field of geotechnical engineering used to measure shear wave velocity in soils, which is effective, reliable and economical. The technology appeared in the 1980s, and it has been widely applied in foreign geotechnical engineering designs after continuous development for over 30 years. However, the development and application of this technology in China are just beginning, and traditional methods depend on borehole drilling are still used for measuring shear wave velocity, that is inefficient, uneconomic and less accurate. Therefore, researches on SCPT which can promote the development of exploration technology in the field of geotechnical engineering in China are of great theoretical significance and practical value.The main works of this thesis are shown as following:(1) Researches have been conducted to study the ever evolving methods of the seismic shear wave survey, and the principles and testing procedure of SCPT which is developed on the basis of static cone penetration test (CPT) technology.(2) Based on theoretical research and requirement analysis, the design of the overall scheme of SCPT testing system is presented, the designing details of software and hardware modules is fully illustrated. These modules include seismic wave sensor based on accelerometer, acquisition module with high precision and high sampling rate, MCU with large RAM, high-speed storage module with high capacity, data transmission module based on CAN bus, trigger with high sensitivity, and easy-to-operate data processing software with friendly interface.(3) After collecting seismic wave signal successfully, the wavelet threshold de-noising algorithm and the cross-correlation algorithm are mainly studied in this paper. In the course of data processing, the seismic signal de-noising will be achieved at first and then the filtered data will be calculated to get precise shear wave velocity.(4) To begin with, multi-functional digital SCPTU testing system is described and the equipment performance is evaluated. In addition, Vertek-Hogentogler SCPTU testing system is also introduced. Ultimately, many in-situ tests have been conducted, and comparisons of the two testing systems have been made to analyze error sources, and verify the accuracy, reliability and practicability in engineering.