Study On Compaction Controlling Index Mark Of Soil

Since the 1990s, the highway construction of our country has developed very quickly. The scale of investment of the highway infrastructure construction is becoming larger and larger year by year. Great achievements which attract worldwide attention were obtained, but at the same time, some problems which require urgent solution appeared.During the progress of highway construction, degree of compaction is an important index of the road bed construction quality control, and is lain general stress on in the road engineering circle. The sizes of the soil granules used in road bed differ much. The compaction of pure fine grained soil can be easily controlled, and the detection and evaluation methods of compaction quality are mature. But there is not so much pure fine grained soil, so some road beds are reclaimed by soil containing some coarse-grained materials. The compaction standard and the compaction property of this kind of soil and its engineering stability under different degree of compaction are important theoretical and practical problems related much to the control of compaction quality of the road bed and the operation stability. In recent years, the frequent occurrence of the early disease in road operation, the quality problems of the road bed construction, especially the influence the soil graduation makes to the compaction property, the compaction mechanics of silt, the problems of the water stability under different degree of compaction attract general attention in the road engineering circle. The soil containing coarse-grained materials is obviously different from the general fine grained soil, so there must be some problems in using the detection and evaluation methods of compaction quality of the silt, such as the determination of the standard dry density, the applicability of the detection and evaluation indexes, the rationality of the evaluation standard, and so on.In this study, the indexes of the physical and mechanical properties of silt, clay soil and coarse-grained materials are measured according to the road earthwork experiment regulations, the People's Republic of China profession standard. Conduct compaction tests to each kind of silt and clay soil which is added by coarse-grained materials under different water content and compaction work, measure their dry density, analyze the data, discuss the change law among the graduation, the dry density and the compaction work, get the function relationship by regression and obtain the optimal compaction work of soils of different graduation.Measure the coefficient of permeability of silt and clay soil under different degree of compaction; analyze the water stability of silt after compaction. Understand further the compaction mechanics of silt and clay soil by analyzing their microscopic structure. Make comparison with the standard compaction in the existing compaction standard, find the problems in the existing compaction standard, propose your own opinions and search for the new compaction standard of the degree of compaction of the road bed.