| At present,the soil curing agent can be divided into calcium-based curing agent and non-calcium-based curing agent.Among them,calcium-based curing agents are widely used in China's engineering,such as cement,lime,fly ash,etc.However,the application of traditional calcium-based curing agent has been followed by many problems such as environment and roadbed diseases.The soil condensate rock is a new type of soil solidifying agent,which is made of industrial waste by grinding and processing(without calcining).It has the characteristics of turning waste into precious and green environment.In this paper,aiming at the low liquid limit clay soil in Zhangjiakou,coagulation rock soil curing agent is the main line,and the cement curing agent is a comparison reference.Through the laboratory tests,it explores the soil condensate rock improved low liquid limit clay mechanics performance and durability.Combined with field test section,it analyzes the soil rock coagulation improved soil pavement performance.The specific contents are as follows:Firstly,the soil samples were tested by particle analysis,compaction,plasticity index and other basic physical indexes,and the soil samples were determined as low liquid limit clay.It describes the properties and characteristics of the soil condensate rock,determines the experimental plan,and provides a direction for the next stage of the soil condensate rock and cement experiments.Secondly,compaction tests were carried out for two kinds of curing agents,and the optimal moisture content and the maximum dry density were determined respectively,so as to provide parameters for the unconfined compression test and subsequent test.Comparative analysis of two kinds of improved soil unconfined compressive strength and the size change trend in different content in different ages and conditions,obtained the soil improved by oil condensate is higher than that of setting a volume level under the same conditions,and the function relationship between the compressive strength and the age and the amount of mixing is obtained by function fitting.The influence factors of the soil strength of the soil condensate are analyzed,and it is concluded that the age is most significant influence factor,the dosage takes the second place,and the degree of compaction is the least significant influence factor.Thirdly,The durability tests of water stability and frost resistance were carried out for two improved soils.Through the unconfined compressive strength test of waterimmersing regimen,it was found that the strength of cement soil was higher than that of standard soil,and the soil condensate rock improved soil decreased,but the same content,the same age stage cases,the improved soil condensate rock soil is up to or higher than that of cement soil.By conducting freeze-thaw cycle tests at different health ages,frost resistance analysis was performed on the unconfined compressive strength,strength loss rate,mass loss rate,specimen surface change,and damage modulus of the two improved soils,it is concluded that: After the freeze-thaw cycles of different ages,the two modified soils will have different changes in the above aspects.Regardless of 28 d or 90 d,the compressive strength decreased after 5 or 7 freeze-thaw cycles,and after 28 days,the strength increased with the number of cycles after 7 freeze-thaw cycles.When 90 d is frozen and thawing cycle,the strength still decreases or does not increase.Finally,according to the analysis of the laboratory test results and the conditions of site construction,provide a reasonable construction plan and process flow for the test section.It was determined that 8% of the modified low-liquid limit clay was used as the road base material.According to the relevant specifications,The compactness of the test section,the thickness of the road surface,the content of soil condensate rock and the 7d unconfined compressive strength are tested,and the results are all up to the relevant specifications and design requirements. |
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