Abstract

In the process of engineering investigation of rock mass, it is of great significance to obtain precise rock structural surface properties for rational design of the project and prevention of geological disasters during construction. A new three-dimensional topological feature description method for the rock face was proposed. This method is based on the circular structural profile line observed in the borehole and digital borehole camera technology application in three-dimensional topographical feature of the rock structure plane. This paper is based on the borehole wall plane development graph as the basic data, the basic information such as the occurrence of rock structural planes on the borehole wall is analyzed, and the structural surface section lines extracted from the borehole plane development diagram of the digital image processing technology are used. According to the three-dimensional information feature of the profile line on the structural wall of the hole wall, the profile feature parameters of the profile lines in each direction are calculated, and the structural surface is formed by referring to the correspondence between the profile feature parameters and the structural surface roughness coefficient (JRC). Then the roughness coefficient rose diagram is made to describe the three-dimensional roughness of the rock structure surface.

1.
Introduction

In recent years, China has gradually attached importance to the use of underground space in cities and the exploration and development of deep resources. Many major projects have gradually been put on the agenda, and engineering safety issues have also increased. The use of test technology by engineering designers to obtain precise and accurate engineering properties of deep rock masses is of great significance to the rational design of the project and the prevention of geological disasters during construction.

The study of rock structural planes is the basic work of analyzing the engineering properties of rock masses. Numerous studies and experiments have shown that the mechanical properties of the rock face are not only related to the characteristics of the wall rock and the combined state of the face, but also affected by the surface morphology of the face.

For a hard structural surface with a small degree of filling, the surface morphology of the structural surface is the main influencing factor controlling the mechanical properties of the structural surface (Gao et al.,2010). However, obtaining information on deep rock structural planes by drilling and coring has many limitations. First, during the core drilling process, due to the rotational displacement of the core, the exact information of the rock structural plane is destroyed. Secondly, the disturbances such as high-speed rotation of the drill bit and the circulation of the drilling fluid in the coring tube generate a structural plane on the core affect the determination of structural surface closure (openness) and structural surface filling. It can be seen that using core data as a source of rock structural plane information is not accurate enough. Therefore, it is necessary to propose an in-situ measurement technique to directly measure the structural plane of the hole wall of the drilled hole and obtain the surface morphology information of structural plane on the hole wall.

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