The analysis of causing the soil nailing technology failure reason
Soil nailing as a kind of active supporting technology,the proportion in the roadway support takes more and more, due to it has the convenient construction, simple construction method, good supporting effect, the lighter of the intensity of labor, good adaptability,which has been widely recognized.
Soil nailing is a relatively high technical content support technology, the good or bad soil nailing effect is depends on many factors, either a problem, may cause the failure of soil nailing.
- The main reason for the failure of soil nailing is the change of geological conditions, as we all well known that before tunnel construction, the technical department according to the soil nailing theory, elaborate design and calculation, and calculate the anchor length according to the specific situation, and after a field test to determine the reasonable support parameters, anchor length is mainly according to the scope of the surrounding rock loose circle, if soil nailing parameter design calculation cannot be targeted based on specific geological conditions, which will cause the actual use of supporting parameters can not be very good to adapt to the changes in geological conditions.
- Reduce the exposed length of soil nail, ensure the effective supporting length.In given conditions, the length of soil nail body exposed is long, can decrease the corresponding effective length of soil nail to some extent, soil nailing must be increased maximum anchorage length on the condition of supporting parameters, it is have positive significance to improve the effect of support.
- The material and design of soil nail has a great impact on the bearing capacity of itself.
- The quality of the construction team will have a great influence on the soil nailing effect.It is very complexed in soil nailing process , human factors, such as the Angle of the anchor rod, soil nail hole depth, "the three paths" match situation of soil nailing, the size of the prestressed soil nail and anchor force and so on, each working procedure of construction deviation has great influence on soil nailing quality .
- The timely support of tunnel after excavation and improve the prestressed anchor to enhance the strength of surrounding rock, control the early deformation and destruction of surrounding rock, play its bearing capacity of surrounding rock, which has important significance on improving the effect of bolt support .
- The complete soil nailing safety inspection has an important significance on ensure the effect of bolt support , the concealment of the bolt support has a large imperceptibility , therefore, we must strengthen the engineering quality detection and mine pressure monitoring, in order to timely control the scene of the actual supporting effect.