| With the development of national economy and the need of practical engineering, the development of underground engineering to the deep high stress area is an inevitable trend.Rock blasting is an important threat to the construction process of deep high stress zone,which brings great challenge to the safety of construction personnel and equipment. The mechanism of rock burst is very complex, and the stress process is both pressure and pressure relief. Rock mass under loading and unloading conditions are two completely different stress paths, and the mechanical properties are also different. Because of the large size of the natural rock collection, processing and loading conditions. For larger size samples of the test there are a lot of difficulties. Therefore, it has a unique advantage to carry out the research of indoor physical simulation. Simulation test has a very important role in the research and prediction of rock burst mechanism. It can not only make the process of rock burst in the room, but also help to analyze the changes of stress and strain during the occurrence of rock burst. The selection of similar materials and materials can reflect the mechanical properties of engineering rock mass is a key factor in the success of model test. Because of the extensive nature of the groundwater in the actual project, the presence of chemical ions is often accompanied by the presence of chemical ions, so that the groundwater solution presents different acid and alkali, which affects the mechanical properties of the rock mass. Based on the above situation, this paper studies the dynamic and static mechanical properties of rock burst similar materials, as well as the rock burst similar materials under the action of chemical corrosion. And to carry out the model test of deep tunnel excavation. Provide reference for the construction, design and support of deep rock mass engineering.Firstly, select fine sand, cement, gypsum and water as raw materials, according to the orthogonal design test method, with sand ratio, gypsum cement ratio and water content of 3factors, each factor has 4 levels.Design 16 groups of matching scheme. Determination of the mechanical properties, impact energy index and compressive strength and tensile strength ratio as the indicator selected to satisfy similar material proportion of rock burst. Secondly,according to the selection of rock burst ratio of similar materials making height of 20 mm in diameter is 40 mm cylinder test and height of 125 mm diameter specimens of 61.8mm cylinder,respectively in the split Hopkinson pressure bar(SHPB) and hydraulic press determination of its dynamic and static mechanical properties. The above specimens were placed in the chemical solution of PH=2 and PH=4 for curing, curing for 60 days and 90 days, and then test the dynamic and static mechanical properties. Thirdly, based on the selection of the ratio ofsimilar materials of rock burst, the unloading model test of deep rock mass excavation is carried out. The following conclusions are obtained in this paper:1. Fine sand, cement, gypsum and water are the ideal similar raw materials, the raw materials are easy to obtain and the mechanical properties are stable, which can simulate the rock burst tendency.2. Through the analysis of the mechanical properties and determination of a range of indicators of similar material test, the factors on the mechanical properties of the similar material contribution effect.3. Based on MATLAB programming multiple linear regression equation, the sand mixing rate, gypsum cement ratio and moisture rate as independent variables, we found the density, the impact energy index, compressive strength, tensile strength and compressive strength and tensile strength of ratio and proportion of similar materials content of relationship and fitting is used to obtain the regression equations for each.4.Under chemical corrosion, similar material static and dynamic compressive strength decreased, the greater the acidity strength is low. A chemical solution curing time is longer,lower intensity. The loading rate increases, the dynamic compressive strength greater.5. In the process of excavation unloading, the greater the unloading rate is, the more obvious the damage is, the greater the stress is, the faster the crack development and the worse the stability of the roadway. |
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