Research on the Damage and Failure of Soil Moisture Infiltration in Roadbed under Rainfall Conditions
In response to the problem of asphalt pavement cracks caused by rainwater infiltration affecting the roadbed soil,such as frost heave,experimental research is conducted based on the influence of water infiltration on the silty clay roadbed.During the experimental research process,a fixed moisture content roadbed soil sample with a complete pavement structure layer that is not affected by rainfall moisture was selected,and a variable moisture content roadbed soil sample with a cracked pavement structure layer that is affected by rainfall moisture content was selected.Unconfined compressive tests were conducted on powder clay samples under different conditions.The results indicate that:(1)Under compression,the failure modes of fixed moisture content specimens mainly include four types:shear failure,tensile failure,conjugate tensile shear failure,and splitting tensile failure.After water infiltration,the wetting front of the sample appears as a horizontal circular downward infiltration,while the wetting front of the variable moisture content sample appears as a"V"shaped downward infiltration after rainfall water infiltration,forming a preferential flow state.(2)The stress-strain curve of the roadbed soil sample after unconfined compression test can be divided into:compaction stage,linear elastic deformation stage,yield stage,and fracture stage;The unconfined compressive strength decreases with the increase of moisture content and rainfall,the stress peak of the stress-strain curve of the sample decreases and moves back,and the strain range in the stable stage increases.(3)Under variable moisture content rainfall conditions,the unconfined compressive strength of the sample decreases by about 14％compared to the compressive strength of the fixed moisture content sample under three different rainfall conditions:small,medium,and large,with a constant initial moisture content of the sample.
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