土壤固化剂改善红层土边坡抗冲刷性试验研究

发布时间：2018-04-26 20:12

本文选题：红层土边坡 + 土壤固化剂　；参考：《西南科技大学》2017年硕士论文

【摘要】：红层在我国的分布广泛,其中西南地区的红层是分布最广泛、最具代表性的,西南地区红层主要分布于四川省、重庆市以及四川盆地边远地区。红层具有粘土矿物含量高、固结陈化差、层间结合不良、软硬相间成层的特点,因此其土质强度较低、遇水后易崩解、软化性高、单轴抗压强度低等不良力学特性。本文采用固化剂固化四川绵阳地区红层土。通过室内土工和人工模拟边坡冲刷试验,研究了固化红层土的抗压强度、抗剪强度、抗渗性及水稳性的影响因素和规律,分析了影响边坡坡面稳定的主要因素,并探讨固化剂固土方法对提氋边坡稳定及抗冲刷性的防护效果。主要研究成果如下:(1)素红层土水稳性极差,内摩擦角为25.20°,且黏聚力为8.82k Pa,抗压强度为50k Pa,红层土土边坡工程会由于强度低而容易发生边坡失稳破坏。两种固化剂,三种加固方法均能有效提高红层土的抗剪、抗压强度及水稳性。并且黏聚力C比红层土增大了23.0%~200.9%,内摩擦角φ比红层土增大了3.1%~82.6%,无侧限抗压强度提高了31.3%~504.8%。(2)红层土抗剪、抗压强度的影响因素主要包括固化剂掺量及养护龄期。固化红层土的内摩擦角、黏聚力和无侧限抗压强度均随着固化剂掺量、养护龄期的增加而增加,但需注意的是,粘土石化剂和水泥混合料固化的试件,水泥掺量较高时,随粘土石化剂掺量的增大,固化土试件抗剪及抗压强度虽继续增大但增幅降低,特别地,当水泥掺量为5%时,固化土强度增幅降低明显,并且黏土固化剂对重塑试件无侧限抗压强度有一定的“修复”作用,使试件破坏重塑后,无侧限抗压强度的损耗降低。(3)影响素红层土和固化土边坡坡面稳定及抗冲刷性能力强弱的主要因素有放水流量和边坡坡度。随放水流量和坡度的增大,径流量也持续增大。冲刷产固体颗粒量和径流含固体颗粒量随放水流量的增大而增加,随边坡坡度的增大呈先增大后减小的变化趋势,其极限坡度值为45°。不同放水流量和坡度条件下,径流强度的变化趋势相同,在冲刷起始阶段(0~5min)内,增加幅度较大,5min后增大趋势变小,并逐渐趋于稳定,并且放水流量对径流强度的影响较大,坡度对径流强度的影响较小。(4)掺入固化剂后,与素土边坡相比,固化土边坡坡面的含沙总量降低了62.23%~77.86%,含沙总量明显减少,且与素土坡面相比,固化土坡面的径流含固体颗粒量降低明显,并且径流含固体颗粒量随冲刷时间延长的变化幅度较小。说明固化剂对降低坡面径流含固体颗粒量,提高坡面抗冲刷性的防护效果显著。综合考虑水泥和粘土石化剂对红层土力学特性及边坡抗冲刷性的影响,建议在四川地区的红层土边坡加固工程中应用水泥和粘土石化剂混合料进行加固,其中水泥最佳掺量为4%,粘土石化剂最佳掺量为5%,养护龄期达到7d以上,能明显提高边坡土壤力学特性及抗冲刷性,防止因坡面侵蚀而产生的边坡失稳。
[Abstract]:The red layer is widely distributed in China, of which the red layer in the southwest is the most widely distributed and most representative. The red layer in the southwest is mainly distributed in Sichuan, Chongqing and the remote areas of the Sichuan basin. The red layer has the characteristics of high clay mineral content, poor consolidation and aging, poor interlayer binding and hard and hard interphase formation, so the soil strength is strong. Lower, easy to disintegrate after water, high softening, low uniaxial compressive strength and low mechanical properties. The curing agent was used to solidify red layer soil in Mianyang area of Sichuan. The influence factors and laws of the compressive strength, shear strength, permeability and water stability of the solidified red layer soil were studied by the indoor soil engineering and artificial simulated slope scour test. The main factors affecting slope stability are discussed, and the protective effect of solidifying agent on slope stability and resistance to erosion is discussed. The main research results are as follows: (1) the water stability of the red layer soil is very poor, the internal friction angle is 25.20 degrees, the cohesive force is 8.82k Pa, the compressive strength is 50K Pa, and the red layer soil slope engineering will be easy because of the low strength. Two kinds of curing agents and three reinforcement methods can effectively improve the shear resistance, compressive strength and water stability of the red layer soil, and the cohesive C is more 23.0%~200.9% than the red layer soil, and the internal friction angle is more 3.1%~82.6% than the red layer soil, and the unconfined compression strength improves the shear resistance and the compressive strength of the red layer soil. The main factors include the amount of curing agent and the curing age. The internal friction angle, cohesive force and unconfined compressive strength of the solidified red soil increase with the increase of curing agent and curing age, but it should be noted that the clay fossilization agent and cement mixture are solidified and the content of water mud is higher, with the increase of the content of clay petrochemicals. The shear strength and compressive strength of the specimens continue to increase, but the increase in the growth rate is reduced, especially when the cement content is 5%, the strength of the solidified soil decreases obviously, and the clay solidifying agent has a certain "repair" effect on the unconfined compressive strength of the remolded specimens. The loss of the unconfined compressive strength is reduced after the specimen is destroyed and remolded. (3) influence of the vegetarian red The main factors of slope stability and anti scouring ability of soil and solidified soil slope are the discharge flow and slope gradient. With the increase of the discharge flow and slope, the volume of the solid particles and the solid particles in the runoff increase with the increase of the discharge flow, which increases first and then decreases with the slope of the slope. The change trend is 45 degrees. Under the conditions of different discharge flow and slope, the change trend of runoff intensity is the same, in the beginning of the scouring stage (0~5min), the increase is larger, the increasing trend becomes smaller after 5min, and gradually tends to be stable, and the discharge flow has great influence on the runoff strength, and the slope has little effect on the runoff strength. (4) compared with the plain soil slope, the total amount of sand content in the slope surface of the solidified soil slope is reduced by 62.23%~77.86% and the total sediment content is obviously reduced, and the runoff containing solid particles in the solidified soil slope is obviously lower than that of the plain soil slope, and the change of the runoff containing solid particles with the erosion time is smaller. The effect of reducing the amount of solid particles on slope runoff and improving the erosion resistance of slope is remarkable. Considering the effect of cement and clay petrochemicals on the mechanical properties of red layer soil and the anti scouring property of slope, it is suggested that cement and clay petrochemicals mixture should be used to reinforce the red layer soil slope reinforcement project in Sichuan. The best cement is the cement. The amount of admixture is 4%, the best dosage of clay petrochemicals is 5%, and the curing age reaches more than 7d. It can obviously improve the soil mechanical properties and anti scouring property of the slope, and prevent the slope instability caused by the slope erosion.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43;TU411

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