Experimental Research On Compaction Property And Energy Consumption Of Coarse-grained Red Sandstone Soil By Static Compaction

A large number of foundation and subgrade are reinforced by static compaction in engineering. But the research on energy consumption of static compaction is still insufficient. To research compaction property and energy consumption of coarse-grained red sandstone soil, different water content, different coarse grain content and different thickness of coarsegrained red sandstone soil static load compaction tests were conducted by using electronic universal testing machine. The Experiment got the following main conclusions:1. In the compaction test of coarse-grained red sandstone soil, relationship between the stress and strain is exponential. relationship between the compression modulus and stress terminal value is linear. Three stages are included by the following order during compaction process:rapid compression deformation stage,slow compaction deformation stage and stable compaction stage. In each static compaction stage, the coarse-grained red sandstone soil show different deformation features2. Analogy with the unit-volume static compaction work in compaction test, put forward the unit-volume static compaction work in static compaction test. Based on the principle of function, put forward the computing formula of the unit-volume static compaction work. The results show that the relationship between unit-volume static compaction work and dry density can be describe as logarithm relation. The formula reflect the energy consumption of static compaction.3. Under the certain unit-volume static compaction work, only when the water content is optimum, the soil can be compacted to the densest state. The optimum water content of coarse-grained red sandstone soil is 8.3%. When water content is higher than the optimum water content, the effect of increasing unit-volume static compaction work to improve the soil dry density is not obvious.4. Under the certain unit-volume static compaction work, only when the coarse grain content is optimum, the soil can be compacted to the densest state. The optimum coarse grain content of coarse-grained red sandstone soil is 60%. Consider the optimal coarse grain content as one of the compaction characteristics of coarse-grained soil. When the coarse grain content is higher than the optimal coarse grain content, soil gradation is poor, with the increase of coarse grain content, the dry density decreased significantly, and the effect of increasing unit-volume static compaction work to improve soil dry density is not obvious.5. Under the certain unit-volume static compaction work, with the increase of the thickness of coarse-grained red sandstone soil,soil dry density decreases gradually. When the thickness of coarse-grained red sandstone soil is large, the effect of increasing unit-volume static compaction work to improve soil dry density is not obvious. Compacting the soil to the same dry density, the smaller thickness of soil layer, the smaller unit-volume static compaction work. Therefore, appropriately reducing the soil compaction thickness is beneficial to the soil compaction, reducing energy consumption.The research results have a certain significance to enrich the theory of soil mechanics, also have some practical value to guide the design and construction of static pressure reinforced soil.