盾构尾泥的一种固化改良新方法对比试验研究

    EXPERIMENTAL ON THE PERFORMANCES OF SHIELD SLURRY SOLIDIFIED SOIL THROUGH A NEW CURING AGENT BASED ON SOLID WASTE

    • 摘要: 采用低品位硅藻土和磷石膏、电石渣等固体废弃物为原材料制备新型固化剂,以二灰土作为传统固化剂参照,针对固化盾构尾泥试样,开展界限含水率、渗透性、无侧限抗压强度、水稳性、抗干湿循环、重金属浸出等试验,对比分析新型固化剂和二灰土对盾构尾泥的固化效果,并采用碳排放指标,阐明新型固化剂的碳排放影响。试验结果表明:盾构尾泥的界限含水率随固化剂掺量增高而逐渐增大;新型固化剂改良的固化土具有良好的力学性质及耐久性,固化剂掺量为8%时,满足相关规范对路面基层填料的要求。干湿循环对新型固化剂改良固化土的强度损失主要发生在前2次,随后趋于稳定,强度残余系数稳定在0.6左右,二灰土经过3次干湿循环后崩解;综合考虑碳排放量及固化土强度,相比于水泥、二灰土,当固化土得到单位强度提升时,新型固化剂可以分别减少CO2排放量76%和81%,具有很好的环境效益,符合当前“双碳理念”。

       

      Abstract: Using low-quality diatomite, phosphogypsum, and carbide slag as raw materials, with traditional lime-fly ash as the control curing agent, experiments were conducted to evaluate the boundary moisture content, permeability, unconfined compressive strength, water stability, dry-wet cycle resistance, and heavy metal leaching characteristics of solidified shield tail slurry. The curing effects of the novel curing agent and diatomaceous soil on the shield slurry were systematically compared. Carbon emission indicators were introduced to assess the environmental impact of the new curing agent. Test results indicate that the boundary moisture content of the shield slurry gradually increases with higher curing agent content. The soil treated with the novel curing agent exhibits improved mechanical properties and durability. At a curing agent content of 8%, the material meets the requirements specified in relevant standards for use as pavement base filler. Strength loss of the modified solidified soil under dry-wet cycling primarily occurred during the first two cycles, after which it stabilized. In contrast, the lime-fly ash solidified soil disintegrated after three dry-wet cycles. In terms of carbon emissions and strength performance, compared to cement and lime-fly ash, the novel curing agent reduces CO2 emissions by 76% and 81%, respectively, per unit strength improvement of the solidified soil. This demonstrates significant environmental benefits and aligns with the current"dual carbon" goals.

       

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