Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and location ＆ frequen...Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and location ＆ frequency of joints or voids. This paper focuses on improving rock characterization algorithms for instrumented roof-boRer systems. For this purpose, an improved void detection algorithm is proposed, where the underlying theory is built upon the concept of mean change detection based on the feed pressure signals. In addition, the application of acoustic sensing for void detection is examined and it is shown that the variance of the filtered acoustic signal is correlated to the strength of the material being drilled. The proposed algorithm has been validated on the data collected from full-scale drilling tests in various concrete and rock samples at the J. H. Fletcher facility.展开更多
The paper presents an analysis and a subsequent refurbishment of significant buildings in Slovakia. The analysis focuses on the load-bearing timber roof-structures. There are three sacral objects and one long-span spo...The paper presents an analysis and a subsequent refurbishment of significant buildings in Slovakia. The analysis focuses on the load-bearing timber roof-structures. There are three sacral objects and one long-span sporting hall presented. The paper tries to introduce the background of difficult refurbishment process. Before the refurbishment, a thorough process of investigation is required This process includes four basic steps. General information about the load-bearing structure is obtained from the geodetic survey that foregoes the process of diagnostic inspection. The diagnostic survey focuses on the defects of the structure, their degree and possible origin. Modem methods of computer modelling help to understand the structural operation and help to find reserves of carrying capacity. Structural analysis should take into account all detected defects and the joint types, which can influence the transfer of forces. The refurbishment project is usually a brief, but clear summary for fulfilling the needs of Monument Board and building process. All the steps require knowledge from different fields and require professional approach.展开更多
基金funded by National Institute of Occupational Safety and Health (NIOSH) ground control group under the contract No. 211-2011-41138
文摘Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and location ＆ frequency of joints or voids. This paper focuses on improving rock characterization algorithms for instrumented roof-boRer systems. For this purpose, an improved void detection algorithm is proposed, where the underlying theory is built upon the concept of mean change detection based on the feed pressure signals. In addition, the application of acoustic sensing for void detection is examined and it is shown that the variance of the filtered acoustic signal is correlated to the strength of the material being drilled. The proposed algorithm has been validated on the data collected from full-scale drilling tests in various concrete and rock samples at the J. H. Fletcher facility.
文摘The paper presents an analysis and a subsequent refurbishment of significant buildings in Slovakia. The analysis focuses on the load-bearing timber roof-structures. There are three sacral objects and one long-span sporting hall presented. The paper tries to introduce the background of difficult refurbishment process. Before the refurbishment, a thorough process of investigation is required This process includes four basic steps. General information about the load-bearing structure is obtained from the geodetic survey that foregoes the process of diagnostic inspection. The diagnostic survey focuses on the defects of the structure, their degree and possible origin. Modem methods of computer modelling help to understand the structural operation and help to find reserves of carrying capacity. Structural analysis should take into account all detected defects and the joint types, which can influence the transfer of forces. The refurbishment project is usually a brief, but clear summary for fulfilling the needs of Monument Board and building process. All the steps require knowledge from different fields and require professional approach.
