| Two-thirds of the lands in our country are mountainous areas,with the rapid development of economy in our country in recent years,the pace of western development is deeply carryed out,urbanization and infrastructure construction speed has been accelerated,it is unable to avoid to build some important committee,power,transportation and even national defense buildings or facilities under the hillsides or in the valley.They are suffering the rockfall hazards and its protection and management becoming an important task that must be faced in the process of development in mountainous areas.But the research in this area is just getting started,the main method is to carry out related experimental study.In view of this,this paper designed and built the impact test platform based on the research goal,at the same time,used the reinforced concrete slab with building exterior insulation materials under rockfall impact to carry out the experimental study.In this paper,based on the targets and contents of the national natural science fund on the research of the destruction mechanism of rockfall impact on the power structures and its protective measures,the project team designed and built the rockfall impact test platform.At the same time this paper depended on the platform to carry out the impact test,combined with the thickness and different kinds of building exterior wall thermal insulation materials for the assessment of buffer materials in the resistance of rockfall impact,comprehensively considering its protection and heat preservation function,to provide references in the design of reinforced concrete slab.In this paper,the main research and working contents and conclusions are as follows:1?Confirm the parameters of the impact test platform and then build.In order to simulate rockfall impact more realistic,the experiment chosed two reinforced concrete slabs.Its size(long×wide×thick): 1?2m×2m×0.08 m and 2?0.8m×0.8m×0.08 m.The basis of test platform is the board basis,it has nicely integrity.The height of test rockfall tower is 20 m,cantilever overhung 3.5m.Overhanging point and the plate center are on the same midperpendicular and the tower is composed of equal angle steel.The impact block is made of reinforced concrete,M=46.5kg.2?Study on the different buffer(insulation)materials under the impact of the block,and carry on its comparative analysis.The acceleration and impact force data showed that with the same block and impact energy,the XPS board and EPS board with flame retardant added can provide good cushioning effect,and as a durable heat preservation of exterior wall thermal insulation material,they also have good fireproof performance,to be the cost-effective protective materials.3?Explore the damage mechanism of different buffer(insulation)boards under the action of the impact,measuring the damaged scope and the depth of the rear panel,to evaluate the secondary shock resistance of the buffer(insulation)boards.Test data showed that the XPS boards and aluminum silicate boards itself were seriously damaged after once impact,they were difficult to resist the secondary impact,whereas the EPS boards and rock wool boards could continue to resist impact for many times.4?Carried out the static loading tests for different kinds of buffer(insulation)materials,to obtain the stress-strain curves,discussed the energy dissipation capacity of various kinds of materials.Experimental data showed that,for all belong to mineral processing board: rock wool board and aluminum silicate board,the surrounded area of stress-strain curve of rock wool board is larger than silicate aluminum board.For all belong to chemical synthesis of XPS board and EPS board,the surrounded area of stress-strain curve of XPS board is larger than EPS board,respectively shows that rock wool board and XPS board has good energy-dissipating capacity. |
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