不同碳酸钙掺量压实黄土的力学性能试验研究

本着倡导“绿色环保”新时代新型生产的生态理念,本文为了探讨碳酸钙改良黄土强度和湿陷性的可行性,针对陕西洛川黄土抗剪强度和湿陷特性,采用0%、5%、10%、20%和25%质量比的碳酸钙粉末掺入黄土的方式,进行固结慢剪试验和湿陷性试验。结果表明：改良黄土试样的脆性随碳酸钙掺量增加而增大,当碳酸钙含量较低时,试样剪应力-剪切位移曲线为应变硬化型,碳酸钙掺量达到20%时应力-应变曲线呈软化型；在81%、87%、93%压实度下,不同掺量碳酸钙改良黄土的抗剪强度均显著提高,粘聚力和内摩擦角均随着碳酸钙掺量的增加而增大；而对黄土湿陷性的改良效果与压实程度有关,湿陷系数随压实度的增大显著减小,达93%压实度时碳酸钙改良黄土试样的湿陷性全部消除。因此,使用碳酸钙进行黄土的改良,能够取得填筑黄土抗剪强度增大、湿陷性降低的显著效果,而且“绿色环保”。

Experimental study on the mechanical properties of compacted loess with different calcium carbonate content

In line with the ecological concept of advocating the new era of "green and environmental protection" new production methods, The purpose of this paper is to discuss the feasibility of improving the strength and collapsibility of loess with calcium carbonate, aiming at the shear strength and collapsibility characteristics of Shaanxi Luochuan loess, the method of mixing the loess with calcium carbonate powder of 0 %, 5%, 10%, 20% and 25% by mass loess, and then carrying out the consolidated slow shear test and collapsibility test. The results show that the brittleness of the modified loess sample increases with the increase of calcium carbonate content. When the calcium carbonate content is low, the shear stress-shear displacement curve of the sample is strain hardening, and when the calcium carbonate content reaches 20%, The curve is strain-softening type; under the compaction degree of 81%, 87%, and 93%, the shear strength of the modified loess with different calcium carbonate content is significantly improved, and the cohesion and internal friction angle are all increased with the calcium carbonate content. The improvement effect on the collapsibility of loess is related to the degree of compaction. The collapsibility coefficient decreases significantly with the increase of the degree of compaction. When the degree of compaction reaches 93%, the wetness of the loess sample is improved by calcium carbonate. The sinking is significantly weakened. Therefore, the use of calcium carbonate to improve loess can achieve significant effects of increasing the shear strength of filled loess and reducing collapsibility, and it is "green and environmentally friendly.