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为了研究冻融循环对铅污染土固化体工程特性的影响规律及其作用机制,开展了不同压实度试样(90%,96%)的冻融循环试验。通过对经历不同冻融循环次数(0,3,6,10次)作用后的试样进行无侧限抗压强度、渗透和溶出特性试验,探讨了冻融循环作用对铅污染土固化体工程特性的影响规律。试验结果表明,冻融循环作用对不同压实度试样有着不同的影响规律。随着冻融循环次数增加,90%压实度试样的抗压强度降低、渗透性增大、铅浸出浓度增大,而96%试样呈现出相反的规律,即冻融循环对高压实度试样影响不大。为了探索冻融循环作用对铅污染土固化体工程特性影响的微观机制,开展了不同冻融循环作用下试样微观结构试验。试验结果表明,冻融循环对高压实度(96%)试样微观结构影响不大,随着时间的延长,试样内颗粒团聚,孔隙减小,试样内孔隙以颗粒间和团粒内孔隙为主;而冻融循环作用使低压实度试样(90%)孔隙增大,试样内颗粒团聚,团粒间大孔隙占主要比重,这是导致低压实度铅污染土固化体工程特性的劣化的根本原因。
In order to study the influence of freeze-thaw cycles on the engineering characteristics of lead-contaminated soil and its mechanism, freeze-thaw cycles of different compaction samples (90%, 96%) were carried out. The unconfined compressive strength, infiltration and dissolution characteristics of the samples subjected to different cycles of freeze-thaw cycles (0, 3, 6, 10 times) were studied. The effects of freeze-thaw cycles on the solidification of lead contaminated soil Characteristics of the law. The experimental results show that the freeze-thaw cycles have different effects on different compaction samples. With the increase of the number of freeze-thaw cycles, the compressive strength of 90% compaction samples decreased, permeability increased, lead leaching concentration increased, while the 96% samples showed the opposite law, that is, the freeze-thaw cycles of high pressure Solid sample has little effect. In order to explore the microscopic mechanism of the effect of freeze-thaw cycles on the engineering characteristics of lead-contaminated soil solidification, microstructural tests of the specimens under different freeze-thaw cycles were carried out. The experimental results show that the freeze-thaw cycles have little effect on the microstructure of high compressive strength (96%) samples. With the extension of time, the particles in the sample are agglomerated, the pores decrease, and the pores in the sample are intergranular and intragranular The main effect of freeze-thaw cycle is that the porosity of the low-compaction solid sample (90%) increases, the agglomeration of the particles in the sample and the large proportion of the intergranular macroporosity lead to the solidified body of lead contaminated soil The root causes of deterioration of engineering properties.