122级配砂石回填施工工艺标准（122 graded gravel backfill construction process standards）.docVIP

122级配砂石回填施工工艺标准（122 graded gravel backfill construction process standards） Table of contents 1 Scope 1 2 reference standard 1 The 3 term 1 4 material requirements 1 5 preparation for construction 1 6 operation process 1 7 quality control 1 8 quality standards 1 9 product protection 1 Graded gravel backfill construction technology standards 1 scope of application This standard is applicable to the construction of the gravel foundation, foundation treatment and ground cushion. 2 reference standard Specification for acceptance of construction quality of building foundation (GB50202 - 2002) The 3 term Natural sand, formed by natural conditions, the particle size of rock particles in 5 mm below. The natural sand particles in sand, particle size greater than 0.25 mm over the whole weight of 50%. Natural sand - sand particle size greater than 0.5 mm more than 50% of the total weight of particles. Natural sand fine sand particle - particle size greater than 0.074 mm over the whole weight of 85%. Rock particles from natural rocks or pebbles, gravel crushing, sieving and particle size greater than 5 mm. The pebble - caused by natural conditions, rock particle size greater than 5 mm. The content of clay content, particle size less than 0.080 mm particles. 4 material requirements 4.1 natural gradation gravel or artificially graded gravel, should be used in the sand, coarse sand, hard texture of broken stone, stone chips (egg). In the absence of medium and coarse sand area, the fine sand, but also mixed with a certain amount of crushed stone or gravel, its content should meet the design requirements, requirements of good gradation. 4.2 graded aggregate materials, shall not contain roots, waste and other organic debris. As the drainage consolidation foundation, mud content should not exceed 3%. The maximum particle size of crushed stone or gravel cushion thickness or not greater than 2/3, and should not be greater than 50 mm. 5 construction preparation 5.1 main equipments Bettle,