冻融对AS型固化剂改良土工程特性的影响

Influences on Engineering Properties of AS Firming Agent Modified Soil by Freeze-thaw Cycles

通过室内动静三轴试验,研究了Aught-Set(AS)型土壤固化剂改良土的抗冻融耐久性,分析了AS型固化剂改良土的应力应变关系、静强度、动模量和临界动应力与龄期、冻融次数以及冷却温度等影响因素的相互关系。结果表明,试样的7d无侧限抗压强度达到28d的75%;AS型固化剂改良土的应力应变关系为应变软化型曲线,呈脆性破坏形式;其静强度、临界动应力以及动回弹模量均随冻融次数增加呈指数形式衰减,且经历6次冻融后均趋于稳定;同一动应力水平下,冻融作用使得试样的累积塑性变形由变形稳定状态向变形破坏过渡;试样在经历多次冻融循环以后,负温越低对试样的力学特性影响越小。

To study the freeze-thaw durability of Aught-Set（AS） firming agent modified soil,a series of triaxial tests were conducted.The mutual relationships between stress-strain relationship,static strength,dynamic modulus and critical dynamic stress of AS firming agent modified soil and curing time,freeze-thaw cycles,cooling temperature were deeply analyzed.The results show that the unconfined compressive strength of 7 d is 75% than that of 28 d.The stress-strain curves of AS firming-agent modified soil are strain-softening and in brittle failure shape.The static strength,critical dynamic stress and resilient modulus decrease in exponential form with the increase of freeze-thaw cycles,and after 6 cycles of freezing and thawing,the trend is stable.Under the same dynamic stress,the cumulative plastic strain of samples develop from stable state to failure because of freezing and thawing.After many times of freeze-thaw cycles,the lower the negative temperature,the little influence on the mechanic properties.