The failure mechanism of tunnel is more complex under the high geostress and high ground temperature action for deep hard rock tunnel. Loading-unloading triaxial tests on granite under different temperatures were carried out. The complete stress-strain curves of rock，mechanical parameters of rock，and macro failure types under different temperature conditions were analyzed in detail. The results show that there is a temperature threshold value of 60 ℃–100 ℃. The failure is from ductile to brittle with the temperature increase if the temperature does not exceed the threshold value. Temperature enhanced the brittle damage of hard rock. Shear is the dominant failure mode with the temperature increase. Then based on the test，thermo-mechanical coupling calculation was carried out. The thermal effect of excavation unloading for hard rock tunnel was calculated by using a brittle constitutive model and energy release rate index. The mechanical response to tunnel excavation was analyzed under different ground temperatures. The plastic zone，stress index and energy release value were compared quantitatively under different ground temperatures. The calculation showed that temperature increase would make rockburst intensity increase，and shear zone increase. The result of calculation and test data is consistent，and the analysis could benefit the understanding of brittle failure under high ground temperature.

According to the results of marble loading and unloading tests，marble failure characteristics and energy evolution under different stress paths are studied. Results show that the absorbed total energy  of conventional triaxial compression is higher than that of uniaxial compression. The release velocity of elastic strain energy under conventional triaxial compression is slower than that of uniaxial compression after peak strength. The energy storage limit of conventional triaxial compression is higher than that of uniaxial compression. The peak strength and peak strain increase with the initial confining pressure increasing. Marble failure mode transfers from tension-shear failure to shear failure. The absorbed total energy  and elastic energy increase. But the dissipated energy   has no significant change. Confining pressure has no significant effect on the rate of   and  . The peak strength and peak strain decrease with the unloading velocity increasing. Marble failure mode transfers from shear failure to tension-shear failure. The absorbed total energy  and elastic energy   decrease. But the dissipated energy has no significant change. Unloading velocity has no significant effect on the rate of   and  . The absorbed total energy and peak strength are in a linear relationship. The energy storage limit and peak strength are also in a linear relationship.

Traditional rigid anchor bolts allow the deformation of surrounding rock of roadway generally below 200 mm. The rigid anchor bolts often appear tensile failure because they can?t adapt to the large deformation of surrounding rock. A type of anchor bolts with constant resistance and large deformation was therefore manufatured，which can provide the constant resistance and stable deformation. This type of anchor bolt is mainly composed of a constant resistance device and an elastic rod，which is suitable for supporting the surrounding rock in soft rock or deep roadways to effectively control the engineering disaster of rock burst etc. The anchor bolts of constant resistance and large deformation were tested with an experimental system developed in house. The experimental results show that the maximum value of the accumulated deformation of the anchor bolts with constant resistance is up to 1 000 mm. Field tests were also performed in the roadway support of a typical deep and soft rock mine with good effect.