do you know? The JTGD30-2015 "Code for Design of Highway Subgrade" is now released. As the standard of highway engineering industry, it will be implemented from May 1, 2015. The original "Code for Design of Road and Road Subgrade" JTGD30-2004 and its English and French versions will be abolished at the same time. Xiaobian takes you to understand the new roadbed design specifications! Revised brief outline: a historical evolution JTJ016-93, Technical Specification for Design and Construction of Highway Fly Ash Embankment, JTJ017-96, Technical Specification for Application of Highway Geosynthetics, JTJ019-98, Highway Subgrade Design Specification JTJ013-95, "Code for Design of Highway Subgrade" JTG D30-2004, "Code for Design of Highway Subgrade" JTG D30-2015 Second foreign situation 1. AASHTO 2002 "New and Renovated Pavement Mechanics - Experience Method Design Guide" 2. Japan's "Road Construction Order" 3. European, French standards, specifications, etc. Three revised background         China's highway industry has developed rapidly; JTGD30-2004 has been used for more than 10 years and has accumulated successful experiences and lessons; in the past 10 years, relevant new technologies, new structures, new materials and new processes have emerged; the needs of China's highway subgrade design in the latter period . Comparison of the revised contents of the old and new "Road Subgrade Design Code" Directory change / JTG D30-2004 1. General 2, the term 3. General roadbed 4, roadbed drainage 5, roadbed protection and support 6, the roadbed widened and rebuilt 7. Special roadbed Appendix A, B, C, D, E Directory change / JTG D30-2015 1. General 2, terms, symbols (with changes) 3. General roadbed 4, roadbed drainage 5, roadbed protection and support 6, the roadbed widened and rebuilt 7. Special roadbed Appendix A, B, C, D, E, F, G, H, J, K (with changes) Comparison of the contents of the revised contents of the new and old "Road Subgrade Design Code" Chapter Content Changes / Chapter 1 Chapter 1 of the 2004 edition: "General Provisions", 12 articles. Purpose, scope of application, subgrade engineering requirements, subgrade design principles, subgrade design preparation, subgrade design process, high embankment deep road plan, subgrade design flood frequency, minimum fill height of subgrade in bad road sections, roadbed dynamic design method, “four new” Technical applications, relationships with other regulatory standards, etc. Chapter 1 of the 2015 edition: Still the "General Principles", 7 articles. Purpose, scope of application, roadbed design preparation, roadbed Design principles, subgrade design principles, “four new” technology applications, and other standard specifications. Interpretation: The 2015 version of the subgrade specification has been reduced, the subgrade engineering requirements, the subgrade design process, the high embankment deep road plan, the subgrade design flood frequency, the minimum fill height of the subgrade of the bad road section, and the dynamic design method of the subgrade. Chapter Content Changes / Chapter 2 Chapter 2 of the 2004 edition: "terms", 23 articles. Chapter 2 of the 2015 edition: Revised as "terms, symbols", in which the terminology is 24 and the symbols are 10. Chapter Content Changes / Chapter 3 The third chapter of the 2004 edition is: "General roadbed", 11 articles, 67 strips. General provisions (4), road bed (3), fill roadbed (9), excavation roadbed (7), roadbed filling and excavation treatment (6), high slope embankment and steep slope embankment (10), excavation high slope ( 8), rockfill embankment (7), fly ash embankment (6), roadbed soil (3), roadbed spoil (4), etc. Chapter 3 of the 2015 edition: "General Roadbed", 11 articles, 92 strips. General provisions (8), road bed (10), fill roadbed (11), cut roadbed (6), roadbed fill and excavation treatment (6), high fill roadbed and steep slope embankment (17), deep excavation roadbed ( 8), rockfill embankment (7), lightweight material embankment (8), industrial waste slag embankment (7), roadbed soil and spoil (4). Chapter Content Changes / Chapter 4 Chapter 4 of the 2004 edition: for "subgrade drainage", 3, 20 strips. General regulations (4), surface drainage (10), underground drainage (6), etc. Chapter 4 of the 2015 edition: “Sluor Drainage”, 3 strips, 29 strips. General regulations (6), surface drainage (13), underground drainage (10), etc. Chapter Content Changes / Chapter 5 Chapter 5 of the 2004 edition: "Subgrade protection and support", 7 strips, 45 strips. General provisions (6), slope protection (4), roadbed protection (11), retaining wall (9), slope anchoring (9), soil nailing (3), anti-slide pile (3), etc. . Chapter 5 of the 2015 edition: "Subgrade protection and support", 7 articles, 56 strips. General provisions (6), slope protection (6), roadbed protection (9), retaining wall (12), slope anchoring (12), soil nailing support (5), anti-slide pile (6), etc. . Chapter Content Changes / Chapter 6 Chapter 6 of the 2014 edition: “Roading and Rebuilding of Subgrades”, 4 articles, 25 strips. General provisions (3), the original roadbed condition survey and evaluation (5), the second and second level roads, the roadbed widening and rebuilding (11), the highway, the first road, the original roadbed widening and rebuilding (6). Chapter 6 of the 2015 edition: “Roading and Rebuilding of Subgrades”, 4 articles, 29 strips. General provisions (5), the original roadbed condition survey and evaluation (7), the second and second level roads widened and rebuilt (10), highways, first-class highway subgrade widening and rebuilding (7). Chapter Content Changes / Chapter 7 Chapter 7 of the 2004 edition: "Special Subgrade", 17 articles, 66 strips. General provisions (3), landslide subgrade (4), collapse and rock pile subgrade (3), debris flow area subgrade (2), karst area subgrade (4), soft soil area subgrade (9), red clay and high liquid Subgrade in the restricted area (3), subgrade in the expansive soil area (3), subgrade in the loess area (4), subgrade in the saline soil area (5), subgrade in the permafrost region (5), subgrade in the wind-blown area (4), and snow-covered area Subgrade (3), turbulent ice subgrade (2), goaf subgrade (2), coastal subgrade (5), reservoir subgrade (5), etc. Chapter 7 of the 2015 edition: "Special Subgrade", 19 articles, 139 strips. General provisions (4), landslide section subgrade (11), collapsed section subgrade (6), rock pile section subgrade (6), debris flow section subgrade (6), karst area subgrade (6), soft soil subgrade (15), Subgrade of red clay and high liquid limited soil area (4), subgrade of expansive soil area (8), subgrade of loess area (5), subgrade of saline soil area (11), subgrade of permafrost area (10), subgrade of wind and sand area ( 5), roadbed of snow damage section (10), roadbed of turbulent ice section (6), roadbed of goaf (7), coastal roadbed (5), subgrade of reservoir area (7), subgrade of seasonal frozen area (7), etc. Note: The seasonal frozen zone subgrade (7) is a supplement to the 2015 new edition specification. Comparison of the revised contents of the revised contents of the old and new "Road Subgrade Design Code" Appendix change JTG D30-2004JTG Rock mass classification of A rock slope B Monitoring content and projects C. Peripheral frozen soil highway engineering classification humidity prediction method D Loess Zoning Map E Description of the terms used in this specification JTG D30-2015 Standard Test Method for Dynamic Rebound Modulus of Road A Soil Range and representative value of dynamic rebound modulus of B roadbed soil C roadbed balance D roadbed rebound modulus humidity adjustment coefficient value range E Rock mass classification of rock slope F Subgrade monitoring content and project G retaining wall design calculation H Permafrost Highway Engineering Classification J Loess Zoning Map K Description of the terms used in this specification Attachment: 2015 new edition specification added appendix content A, B, C, D, F Supplementary provisions for the revised content section of the new and old Highway Roadbed Design Code 1) Section 3.2 “Road bed” of the original specification According to the traffic load level – the depth range of the road bed is adjusted; —— The control standard and index estimation method of the rebound modulus of the subgrade structure are proposed. 2) Filling the roadbed - Added "Design principles for the height of the fill road and methods for determining the height of the embankment". 3) High embankment and steep slope embankment - Revised the analysis method of embankment stability; - Added "Stability safety factor and stability analysis method for high fill subgrade under continuous rainfall conditions, seismic conditions". 4) Change the original specification 3.9 “Fly ash embankment” to “Lightweight material embankment”; —— Add “geo-foam embankment” and “foam light soil embankment”; ——Clear light materials Embankment structure design, material design and stability, settlement verification requirements. 5) Add Section 3.10 “Industrial Waste Embankment” ——The technical requirements for the application conditions, material requirements, embankment structure design and embankment stability check calculation of blast furnace slag, steel slag and coal gangue are given. 6) Subgrade drainage - supplemented with "maximum allowable flow rate of open trench", "low embankment drainage", "drainage drainage", "subgrade drainage", "central separation with drainage design", "bleeding" Technical requirements such as “drainage tunnel”. 7) Subgrade protection and support - supplemented the applicable conditions, structural design and material technical requirements of flexible protective structures such as “geogrid reverse-package reinforced earth retaining wall and stone cage retaining wall”; Prestressed anchor structure calculation and anti-corrosion requirements, soil nail application conditions, prestressed anchor cable anti-slide pile design requirements, and field test and monitoring design requirements. 8) Roadbed widening and rebuilding - supplementing the evaluation content of the original roadbed in expansive soil area and karst area; ——Revision: original roadbed field test requirements, broadening roadbed soft soil foundation treatment measures, original roadbed utilization and treatment technical principles and requirements. 9) Special roadbed - Revised landslides, collapses, rock piles, debris flows, karst, soft soil, red clay and high liquid limit soil, expansive soil, loess, saline soil, permafrost, weathering, snow damage, turbulent ice, goaf 16 types of special roadbed design principles, disease prevention measures and technical requirements for coastal and reservoirs; - Increased the subgrade of 7.19 seasonal frozen areas. 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