No abstract

Failure modes of jointed rock mass with different joint dip angle, joint center continuity degree, joint sets, load strain ratio and joint filling width under SHPB test are studied with model tests. The results show that failure modes and dynamic strength of jointed rock mass are much related to joint geometry. To rock mass with a single joint, its strength and failure mode are greatly controlled by the joint dip angle. The dynamic strength of the samples with joint dip angle 0° and 90°, whose failure modes are both tensile failure, is 90% and 71% of that of intact one, respectively. The dynamic strength of the samples with joint dip angle 60° is nearly zero. The dynamic strength of the samples with joint dip angle 30° and 45°, whose failure modes are mainly shear failure with partly tensile failure, is 50% and 18% of that of intact ones, respectively. The dynamic strength of the samples with 1/4, 1/2 and 4/5 joint center continuity degree is 95%, 74% and 28% of that of intact one, respectively. The dynamic strength of the samples with 1, 2 and 3 sets of joints is 54%, 23% and 10% of that of intact one, respectively. The dynamic strength of the intact and jointed samples both increases with load strain ratio, and the sensitivity to load strain ratio of the former is much higher than that of the latter, whose failure mode becomes more complicated accordingly. With increase of joint fillings width, the samples dynamic strength decreases gradually, but its failure mode does not change.

Mining companies intend to solve the problem of waste dump and reduce the production cost by dumping a large number of waste soils to cover slope outside the running tailings. Therefore, in order to discuss the safety of waste dump slope covering in front of the tailings dam, numerical method was adopted to study the seepage-line change law, the pore water pressure and anti-sliding safety before and after the waste dump covering out of tailings dam. The researches show that the key to waste-dump slope safety are the drainage performance of waste dump bottom layer and the anti-sliding safety of waste dump soil. The appropriate waste dump slope work can improves the tailings dams safety and solves the waste dump problem in mining production.

Explosion experiment was implemented on the small tailings dam model, aims to study the explosion effect of tailings sand under the action of the explosion. Explosion experiment includes three phases; experimental points were set respectively in the starter dam, embankment and deposited beach. In this experiment, blasting vibration velocity and vertical displacement of sand body are measured and collected, so did the tailings sand’s moisture content, cracks’ size, blasting crater, water and sand spurt phenomenon. Experimental results show that the buried conditions and tailings dam’s moisture content have a significant impact on explosion effect. By processing the velocity and displacement data, the attenuation law of blast vibration velocity in the tailings dam is reached, the blasting vibration velocity corresponding to crack damage of sand body is predicted, and the relationship between failure phenomenon of the tailings dam and the displacement produced by explosion is obtained.

The article takes tailings dam material as study object. A series tests, including particles analysis test, density test, seepage test, static treaxial test and compression test were conducted to analyze the physical and mechanical properties of heap dam materials. The characteristic curve and data were received. The result can system analysis the deformation laws of dam material. Experiments show that the compression coefficient of tailings is sensitive to void ratio. Through analysis of the strength parameters of the tailings in static triaxial test, it is known that the tailings cohesion can be neglected as 0 and the change of dry density has a larger influence on strength of tailings material.