Current Situation of Rock Bolting Support at Home and Abroad(1)

1. Good support effect

Bolt support is in line with modern rock mechanics and rock control theory in support principle, and belongs to "active" support. After the bolt is installed, the economic benefits in the surrounding rock are obvious.

The use of bolt support can reduce the input of support materials and reduce the cost of direct support. Since the bolt support foundation does not occupy the effective section of the roadway, the construction section is the net section, so in the support design, the roadway section can be correspondingly reduced and a lot of materials can be saved. Bolt support can reduce roadway maintenance and save maintenance costs. In a word, bolt support can reduce costs in terms of supporting materials, auxiliary transportation, section design and maintenance costs, and the economic benefits are obvious.

2. Development status of foreign anchor week technology and theoretical research

In the world's major coal-producing countries, bolting technology has developed rapidly in recent years. Following the United States and Australia, which almost used bolt support in the Ministry of Gold, the United Kingdom also quickly caught up. After several years of development, bolt support has dominated coal mines. At present, Australia and the United Kingdom are promoting their bolt support technology to foreign companies. India, Indonesia, Poland, Japan, South Africa and other countries have introduced it to varying degrees. Germany, which has always been known for its steel retractable support technology, has been actively exploring the feasibility of bolt support in recent years, despite its large mining depth and high ground pressure. These facts show that roadway bolt support technology has become a worldwide development trend.

2.1 About the action of anchor bolts to reinforce surrounding rock

In the United States, because of its shallow tunnel depth, high rock stratum strength and low in-situ stress, the United States tends to the suspension theory and the grouped beam (reinforced rock beam) theory, while the British and Australian roadways are mainly affected by horizontal stress. , especially in Australia compared with the UK, the deformation of the surrounding rock and the maximum horizontal stress of the roadway are more severe. Generally speaking, the design theory of bolt support in the UK and Australia tends to strengthen the arch (extrusion support arch) theory.

2.2 About bolt reinforcement design method

Meiguo currently has two design methods for foundations: one is the empirical method, that is, the design method based on the previous experience in solving rock formation control. The main disadvantage of this method is that it emphasizes the roof control problem itself, and lacks the development status of domestic anchoring technology and theoretical research that causes roof instability.

China began to use bolts in 1955, but only in recent years, my country's anchoring technology, especially coal bolt support technology, has developed rapidly.