Ren Xu, Zhang Zhufang, Xiang Min, Xu Guihong, Cao Wenze
College of Civil Engineering, Guizhou Institute of Technology, Guiyang 550003, China.
Guizhou Highway Engineering Group Co., Ltd., Guiyang 550025, China.
Molecules. 2022 Oct 31;27(21):7404. doi: 10.3390/molecules27217404.
The engineering geological problems of soft rock are common in large slope engineering and underground engineering surrounding rock. In order to study the change in mechanical properties of soft rock under the action of loading, excavation and rainfall, this paper carried out experimental research on similar materials of soft rock. The similar material of soft rock is prepared by using iron fine powder, barite powder and quartz sand as aggregate, gypsum as binder and redispersible latex powder as regulator. A single-factor influence test was designed with the content of redispersible latex powder as variation parameter. Analysis the influence of redispersible latex powder from the perspectives of physical and mechanical indexes, failure forms, stress-strain states and changes after water seepage. In addition, evaluate the feasibility of this similar material in geomechanical model test. Experimental results show that the density, compressive strength and Poisson's ratio of similar materials can be improved to a certain extent by the redispersible latex powder with low dosage. However, the above indexes show a significant downward trend with the increase in dosage when the dosage exceeds 2%. The deformation modulus always shows a downward trend, and this trend becomes more significant especially when the dosage exceeds 2%. With the increase in the redispersible latex powder, the stress-strain curves of similar materials show obvious elastic and plastic stages. The failure mode gradually changes to X-shaped conjugate failure, which is common in soft rock, and the material changes from brittle failure to plastic failure. In addition, this type of similar material with gypsum as cementing agent will cause serious damage and loss of bearing capacity after seepage. These methods produce similar materials with low strength, low deformation modulus and plastic failure form, which can be used to simulate the stability of soft rock engineering caused by loading or excavation. At the same time, it also sheds lights on preparing similar materials of hard rock.
软岩的工程地质问题在大型边坡工程和地下工程围岩中普遍存在。为研究软岩在加载、开挖及降雨作用下力学性质的变化，本文对软岩相似材料开展了试验研究。软岩相似材料采用铁细粉、重晶石粉和石英砂作为骨料，石膏作为胶结剂，可再分散乳胶粉作为调节剂配制而成。设计以可再分散乳胶粉含量为变化参数的单因素影响试验，从物理力学指标、破坏形式、应力应变状态及渗流后的变化等方面分析可再分散乳胶粉的影响。此外，对该相似材料在地质力学模型试验中的可行性进行评价。试验结果表明，低掺量的可再分散乳胶粉可使相似材料的密度、抗压强度和泊松比在一定程度上得到提高。然而，当掺量超过2%时，上述指标随掺量增加呈显著下降趋势。变形模量始终呈下降趋势，尤其是当掺量超过2%时，这种趋势更为明显。随着可再分散乳胶粉掺量的增加，相似材料的应力应变曲线呈现出明显的弹性和塑性阶段。破坏模式逐渐转变为软岩中常见的X形共轭破坏，材料由脆性破坏转变为塑性破坏。此外，这种以石膏为胶结剂的相似材料在渗流后会造成严重破坏并丧失承载能力。这些方法制备的相似材料强度低、变形模量低且具有塑性破坏形式，可用于模拟软岩工程在加载或开挖作用下的稳定性。同时，也为硬岩相似材料的制备提供了思路。
