An Experimental Study on the Preparation of Soft Rock Similar Materials Using Redispersible Latex Powder as a Modifier

Abstract

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.

Development of similar materials for fluid–solid coupling model testing and application in damage constitutive models

“…In regression analysis, it was found that the elastic modulus of similar mudstone materials in the above mix proportions is slightly higher than the requirements in Table 14 . Based on the regulatory effect of re-dispersible latex powder on elastic modulus in the reference 10 , a re-dispersible latex powder with a cement content of 6% was added to the mudstone ratio to obtain the final ratio.…”

“…Lei Zhongdai et al 9 conducted sensitivity analyses on the density, cohesion, compressive8 strength, and other indexes of similar materials through orthogonal experiments. Ren Xu et al 10 found that similar materials bonded with gypsum should be cured for at least 7 days or cured to constant weight. In addition, some scholars have used laundry detergent and hydraulic oil to simulate the viscosity of rocks 11 – 13 .…”