Abstract
To meet the demand of antiseepage and reinforcement of soil dams, a kind of permeable polyurethane grouting material was developed. A visual steady‐pressure grouting test device was designed to study the law of polyurethane diffusion and reinforcement in silt under different pressure, and the interaction mechanism of grout and soil body structure was explored microscopically. The results showed that, with the increase in the grouting pressure, the diffusion speed rose, and the diffusion pattern of grout in the soil also changed from permeation diffusion to permeation splitting. Under the effect of grouting pressure, more tiny cracks will occur in the soil structure, leading to the use of more grout, thus increasing the strength of the consolidated soil by more than 10 times. The results of SEM‐EDS and mercury intrusion test proved that the polyurethane had a significant filling effect on the soil structure, which could effectively reduce the porosity of the soil and cement the soil particles through wrapping, complexing, and hydrogen bonding, thereby improving the soil properties. Moreover, the results revealed from a microscopic perspective that the grouting altered the pore structure of the soil structure through the seepage‐erosion‐splitting coupling effect, but when the grouting pressure exceeded 0.4 MPa, the soil particle and grout would be partially remixed and arranged closely, showing a phenomenon of jet grouting. Finally, the material was used in engineering practice, achieving a satisfactory grouting treatment effect.
Highlights
Dams are an important component in the field of flood control and disaster reduction
When the grouting pressure continued to increase to 0.4 MPa, the phenomenon of high-pressure jet grouting occurred. e skeleton structure of soil around the splitting cracks was broken up, and the soil particles were mixed with the grout while splitting cracks were produced in the soil body, so its diffusion speed further rose after decline, and the stable stage of the pressure in the mold lasted for a shorter time
A nonfoaming permeable polyurethane grouting material was developed, the diffusion law in the silt was studied through lab grouting test, and the effect of grouting on the mechanical properties of soil body was explored using unconfined compressive strength test. e mechanism of action of polymer grouting on the soil body was analyzed via scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and mercury intrusion test, followed by engineering application. e main conclusions are as follows: (1) With the increase of grouting pressure, the macrodiffusion mode of polyurethane in the soil body is changed from permeation diffusion to splittingpermeation diffusion
Summary
Dams are an important component in the field of flood control and disaster reduction. E traditional antiseepage and reinforcement methods of dams include concrete cutoff walls [2, 3], cement-soil mixing piles [4], and high-pressure jet grouting [5]. Advances in Civil Engineering diffusion law and reinforcement effect in silt and clay, mainly because of the granularity of cement-based grout and the relatively dense soil [10]. The performance characteristics of soil particle structure under different grouting pressure remain unclear yet under the macro- and microscale conditions Due to characteristics such as low viscosity, low density, short gelation time, and high strength and strong chemical stability after solidification [23], polyurethane materials have been widely used in the grouting repair of highways [24, 25], dams [26], tunnels [27], and other infrastructures. The material was applied to engineering practice to verify its reinforcement and filling effect on the soil
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