Study on deformation and strength of soft soil under water level fluctuation

The excessive ex traction of gr oundw ater caused obv ious g ro und subsidence in the southeastern co astal areas o f China. Ex plo itatio n restrict ion and artificial r echar ge o f gr oundw ater have significant effects on mitig at ing t he g ro und subsidence. These measures lead to dr ast ic f luct uations o f w ater level and sig nificant sett lement and r ebo und deformation of the widespread so ft soil in the coastal areas. In or der to investig ate t he defo rmation and str eng th o f so ft so il under w ater lev el fluctuat ion, by u2 sing the cy linder mo del ex periment dev ice to simulate w ater lev el fluctuatio n, we conducted hig h2pr essure consolidat ion test, di2 r ect shear test, and triax ial t est on the soft soil aft er differ ent times of wat er level fluctuatio n. Based o n the analy sis o f the influ2 ence deg ree of w ater level fluctuation on the deformation behav io r and str eng th characteristics of soft so il, we presented a rela2 tional ex pression of t he residual str eng th o f soft soil aft er differ ent times of w ater lev el fluctuat ion using initial st rength and w a2 ter content. The test results showed that as the fr equency of w ater level fluctuatio n increased, the deformatio n pro perties of the so ft soil wer e enhanced and the str eng th w as reduced. T he cohesion and internal friction ang le decreased linearly w ith the in2 cr ease of water level fluctuations. T he strength index o f the so ft so il under the same times of water lev el fluctuat ion declined significantly w ith the incr ease of wat er co ntent. The r esults have import ant practical sig nificance and application value on ex ploring the action mechanism of w at er level fluctuation o n gr ound subsidence and bearing capacity chang es, impro ving the level o f scien2 tific decision2making , and m itig ating enviro nmental g eolog ical disasters in coastal cities.

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