Silt has the characteristics of developed capillary pores and strong water sensitivity, and capillary water is an important factor inducing the erosion and slumping of silt sites. Therefore, in order to suppress the effect of capillary water, this article discusses the improvement effect of sodium methyl silicate (SMS) on silt. The effect was investigated by capillary water rise testing and contact angle measurement, and the inhibition mechanism is discussed from the microscopic view by X-ray diffraction (XRD) testing, X-ray fluorescence (XRF) testing, scanning electron microscope (SEM) testing and mercury intrusion porosimetry (MIP) testing. The results show that SMS can effectively inhibit the rise of capillary water in silt, the maximum height of capillary rise can be reduced to 0 cm when the ratio of SMS (g) to silt (g) increases to 0.5%, and its contact angle is 120.2°. In addition, considering also the XRD, XRF, SEM and MIP test results, it is considered that SMS forms a water-repellent membrane by reacting with water and carbon dioxide, which evenly distribute on the surface of silt particles. The membrane reduces the surface energy and enhances the water repellence of silt, and combines with small particles in the soil, reduces the number of 2.5 μm pores and inhibits the rise of capillary water.

Silt has the characteristics of obvious capillary water effect and strong water sensitivity. The flooding of the Yellow River caused the water level in Kaifeng to be high, and the damage of capillary water to the silt site of Kaifeng Zhouqiao site is increasing day by day. In order to improve the waterproof performance of the site soil, three kinds of silicone waterproof materials were selected, and the site soil was improved by internal mixing. The improvement effects of different materials were compared through the capillary water rise test, and the contact angle of the modified soil with the optimal ratio was measured. Microscopic tests were conducted to evaluate its wetting properties and reveal the mechanism of action of the modified materials. The results show that the three kinds of silicone waterproofing agents can improve the waterproofing effect of soil, among which 0.5% sodium methylsilicate modified soil has the most significant waterproofing effect; its capillary water absorption inhibition effect can reach 98.34%, and the contact angle is 137.06. The surface of the modified soil is hydrophobic after the addition of sodium methylsilicate. An evenly distributed waterproof film is thus formed on the surface of the soil particles, which changes the contact mode between the soil particles and strengthens the connection between the soil particles, so that the proportion of large pores decreased. The proportion of mesopores and small pores increased, which made the soil sample more compact. These results explain the improvement of the waterproof performance of the soil sample.

Natural hydraulic lime soil has good mechanical properties; as an earthen ruin restoration material, its durability is insufficient. Despite natural hydraulic lime being a topic that has been studied for several years from different researchers, it has not yet been fully considered for the improvement of durability. This work aims to experimentally investigate the enhancement of the durability properties of hydraulic lime-based. The performance of natural hydraulic limestone by adding sodium methyl silicate and organic silicon is examined and the effect of adding sodium methyl silicate on its performance and microstructure is studied. The 6%, 10%, and 15% lime–soil comparison test blocks of sodium silicate were compared with different lime–soil comparison test blocks not mixed with sodium methyl silicate; in addition to compression resistance, shear resistance, water absorption, and erosion resistance, dry–wet cycles were carried out, as well as microstructure testing and analysis. The results show that the addition of sodium methyl silicate enhances the compressive strength of hydraulic lime-modified soil, reduces its saturated water absorption, reduces its shear strength, improves its resistance to dry and wet cycles, and forms on the surface of the modified soil particles. The hydrophobic layer further improves its erosion resistance and water resistance. When the sodium methyl silicate content is 0.3%, the natural hydraulic lime soil has good mechanical properties and good durability, which is the optimal ratio.

Kaifeng Zhouqiao site is located in the traffic trunk line in Gulou District of Kaifeng City. The dynamic load of urban traffic is large. In addition, the silt has poor stability of its particle skeleton structure, large porosity and poor mechanical performance. Under the action of dynamic load, the soil of the site will suffer from cracking, collapse, unstable deformation and overall stability damage. In order to enhance the stability of the soil, this paper uses sodium methylsilicate and lignin fiber to modify the site soil, evaluates the mechanical properties of the improved soil through the compression and shear tests, evaluates the durability of the improved soil through the dry wet cycle test, and reveals its modification mechanism through the micro experiment, so that the mechanical properties of the site soil can be improved, so as to achieve the purpose of repair and reinforcement. The experiment shows that the effect of improving the compressive strength of soil is the best when the content of sodium methylsilicate is 0.3%–0.5%, and the effect of improving the shear strength of soil is the best when the content of lignin is 0.5%–2%. The maximum mass loss rate of the composite modified sample after 10 dry and wet cycles is only 0.71%. The comprehensive analysis determines that the best proportion of the composite is 0.5% sodium methylsilicate and 2% lignin fiber. The modified soil has good waterproof and mechanical properties.