Low-temperature soil stabilizer and construction method thereof

Abstract

The invention discloses a low-temperature soil curing agent and a construction method thereof, the curing agent comprises a cementing material and water glass, and the mass ratio of the cementing material to the water glass is (3-4): 1; the cementing material comprises the following components in percentage by mass: 54%-84.5% of Portland cement, 10%-30% of fly ash, 5%-15% of superfine slag powder and 0.5%-1% of a flocculating agent. The flocculating agent comprises at least one of cellulose ether, polyacrylamide, polyethylene glycol diacrylate and metakaolin. The construction method comprises the following steps: digging an area to be cured, mixing soft soil obtained by digging with a low-temperature soil curing agent, and then backfilling and curing. The low-temperature soil stabilizer disclosed by the invention is low in price, can be constructed in an environment of not less than 0 DEG C, can remarkably improve the freeze-thaw cycle resistance and strength of soft soil with the excavation depth of 3-4m for the soft soil with the water content of 30-50%, and is beneficial to wide popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil solidification, in particular to a low-temperature soil solidification agent and a construction method thereof. BACKGROUND

[0002] Soil solidification agent, i.e. soil solidification additive, is an additive added into soil to react with inorganic binding material, soil and water at normal temperature to improve the engineering performance of soil. Soil solidification agent is widely used in road engineering, foundation treatment and slope reinforcement engineering due to its significant effect on improving the engineering properties of soil.

[0003] Soil solidification agent can be divided into inorganic, organic, ionic, biological enzyme and composite types according to its main components and mechanism. The composite solidification agent is a new type of solidification material formed by mixing organic and inorganic materials in a certain proportion. Organic soil solidification agent generally has good water stability, while inorganic soil solidification agent generally has good solidification strength. The composite solidification agent combines the advantages of organic and inorganic materials and has attracted widespread attention from researchers in recent years. However, the existing composite solidification agents use a large amount of expensive organic materials, so they cannot be widely used in road construction engineering. Patent CN101597496B discloses a cement-based soil solidification agent which is prepared by mixing the following chemical products in a certain proportion: sodium sulfate, sodium tripolyphosphate, carbonyl diamine, polyacrylamide, sodium dodecyl sulfate emulsifier, triethanolamine, sodium silicate, sodium hydroxide, sodium carbonate, potassium hydroxide and methyl sodium silicate. The agent is dissolved in water to form an aqueous solution with a certain concentration, which is then uniformly sprayed on the cement soil to fully activate the activity of cement and clay minerals, thereby achieving the purpose of solidifying the soil. Patent CN101481238A discloses an environmentally friendly soil solidification agent which is prepared by mixing a certain amount of active activator with slag and aluminosilicate minerals. The agent is cheap and can react with various types of soil in areas without sand and stone to form stable and durable shaped components. The agent has the properties of compression resistance, anti-seepage and frost resistance when mixed with soil in a certain proportion and then compacted and extruded.

[0004] The soil solidification agents prepared by the above patents can improve the strength and water resistance of soil. However, in North China, the environment of the solidified soil is relatively harsh, and the temperature changes greatly in the four seasons. If the anti-freeze-thaw cycle performance of the solidified soil is not good, it will seriously affect the service life of the ground. Therefore, it is urgent to develop a low-temperature soil solidification agent with low price and good anti-freeze-thaw cycle performance, which can be widely used in northern China. SUMMARY

[0005] In order to solve the above technical problems, the application provides a low-temperature soil solidifying agent and a construction method thereof, raw materials of the low-temperature soil solidifying agent are easy to obtain and low in price, and the low-temperature soil solidifying agent can significantly improve the freeze-thaw cycle resistance and soil strength of soft soil in a low-temperature environment through the construction method.

[0006] In a first aspect, the application discloses a low-temperature soil solidifying agent, which comprises cementitious material and water glass, and the mass ratio of the cementitious material to the water glass is (3-4) : 1. The cementitious material comprises the following components in percentage by mass: 54%-84.5% of Portland cement, 10%-30% of fly ash, 5%-15% of slag powder and 0.5%-1% of flocculating agent.

[0007] Preferably, the modulus of the water glass is 2-3.

[0008] Preferably, the type of the Portland cement is PO.42.5 Portland cement.

[0009] Preferably, the grade of the fly ash is F1 fly ash.

[0010] Preferably, the slag powder is S95-grade slag powder.

[0011] Preferably, the flocculating agent comprises at least one of cellulose ether, polyacrylamide, polyethylene glycol diacrylate and metakaolin.

[0012] In a second aspect, the application further discloses a construction method of a low-temperature soil solidifying agent, and the construction method comprises the following steps. Excavation is performed on a to-be-solidified area of soft soil, and the depth of the excavation is 3-4 m; After the soft soil obtained after the excavation is mixed with the low-temperature soil solidifying agent of the first aspect, backfilling and solidification are performed.

[0013] Preferably, the water content of the soft soil is 30%-50%. Preferably, the mass ratio of the soft soil to the cementitious material in the low-temperature soil solidifying agent is (6-7) :(4-3).

[0014] Preferably, the ambient temperature of the to-be-solidified area is greater than or equal to 0℃.

[0015] Compared with the prior art, the application has at least the following beneficial effects: (1) The low-temperature soil stabilizer proposed in this application is prepared by mixing common and inexpensive raw materials and can be widely used in road construction projects. According to the construction method proposed in this application, the low-temperature soil stabilizer can significantly improve the freeze-thaw cycle resistance of soft soil, increasing the freeze-thaw cycle retention rate from 78.5% to 93.5% and the compressive strength from 6.5 MPa to 7.4 MPa. Even for soft soil with a water content of 50%, the freeze-thaw cycle retention rate can still reach more than 90%, which is significantly better than similar soil stabilizer products on the market.

[0016] (2) This application analyzes a large amount of data from construction site sampling and proposes the optimal construction process for the low-temperature soil stabilizer of this application. The excavation depth is 3-4 meters. The soft soil obtained from the excavation is mixed with the low-temperature soil stabilizer in a ratio of (6-7) : (4-3) of cementitious material mass. The mixture is then backfilled and stabilized. This allows the soft soil with a water content of 30%-50% to achieve the optimal freeze-thaw cycle resistance performance at the lowest cost.

[0017] (3) The low-temperature soil stabilizer proposed in this application has very low requirements for ambient temperature. As long as the ambient temperature is not lower than the freezing point, it can be used for construction. Even if the ambient temperature has dropped to the freezing point, it can still achieve a freeze-thaw cycle retention rate of more than 93% for soft soil with a water content of 30%, and the soil compressive strength can reach more than 7MPa. Detailed Implementation

[0018] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Unless otherwise specified, all temperatures mentioned herein are in degrees Celsius, and the preferred embodiments can be freely combined as needed. Those skilled in the art will understand that the data and parameters described in the examples are merely exemplary and do not constitute a limitation of the invention. All components used in the following examples and comparative examples are monomers or compounds known in the art, and all equipment used is equipment publicly known in the art. All components and equipment used in this invention can be obtained commercially or prepared using known techniques.

[0020] This invention discloses a low-temperature soil stabilizer, comprising a cementing material and water glass, wherein the mass ratio of the cementing material to water glass is (3~4):1; the cementing material comprises the following components by mass percentage: 54%~84.5% silicate cement, 10%~30% fly ash, 5%~15% slag powder, and 0.5%~1% flocculant. Preferably, the modulus of the water glass is 2~3. Preferably, the silicate cement is PO.42.5 silicate cement. Preferably, the fly ash is grade F1 fly ash. Preferably, the slag powder is grade S95 slag powder. Preferably, the flocculant comprises at least one of cellulose ether, polyacrylamide, polyethylene glycol diacrylate, and metakaolin.

[0021] This invention also discloses a construction method for a low-temperature soil stabilizer, comprising: excavating a soft soil area to be stabilized to a depth of 3-4 meters; mixing the excavated soft soil with the aforementioned low-temperature soil stabilizer, and then backfilling and stabilizing the mixture. Preferably, the moisture content of the soft soil is 30%-50%. Preferably, the mass ratio of the cementitious material in the soft soil and the low-temperature soil stabilizer is (6-7):(4-3). Preferably, the ambient temperature of the area to be stabilized is ≥0℃.

[0022] The present invention will now be described in more detail with reference to exemplary embodiments. The following embodiments or experimental data are intended to illustrate the present invention by way of example, and those skilled in the art should understand that the present invention is not limited to these embodiments or experimental data.

[0023] The silicate cement used is silicate cement of type PO.42.5.

[0024] The fly ash used is grade F1 fly ash.

[0025] The slag powder used is S95 grade slag powder.

[0026] Example 1 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 3:1; the cementitious material comprises the following components by mass percentage: 84.5% silicate cement, 10% fly ash, 5% slag powder, and 0.5% flocculant. The water glass has a modulus of 2. The flocculant is a cellulose ether.

[0027] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The 5.4 tons of soft soil obtained after excavation were mixed with 4.8 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil moisture content was 30%, the mass ratio of the cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 0°C.

[0028] Table 1 shows the components and proportions of the low-temperature soil stabilizers in Examples 1-10 and Comparative Examples 1-6. Table 2 shows the construction method parameters of the low-temperature soil stabilizers in Examples 1-10 and Comparative Examples 1-6.

[0029] Table 1. Components and proportions of low-temperature soil stabilizer

[0030] Table 2. Construction methods for low-temperature soil stabilizers

[0031] Example 2 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 3:1; the cementitious material comprises the following components by mass percentage: 76.5% silicate cement, 15% fly ash, 8% slag powder, and 0.5% flocculant. The water glass has a modulus of 2. The flocculant is polyacrylamide.

[0032] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The 5.4 tons of soft soil obtained after excavation were mixed with 4.11 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil moisture content was 30%, the mass ratio of the soft soil to the cementitious material in the low-temperature soil stabilizer was 7:4, and the ambient temperature of the area to be stabilized was 0°C.

[0033] Example 3 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 3:1; the cementitious material comprises the following components by mass percentage: 69.5% silicate cement, 20% fly ash, 10% slag powder, and 0.5% flocculant. The water glass has a modulus of 2. The flocculant is polyethylene glycol diacrylate.

[0034] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The 5.6 tons of soft soil obtained after excavation were mixed with 4.98 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 35%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 3°C.

[0035] Example 4 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 3:1; the cementitious material comprises the following components by mass percentage: 62.5% silicate cement, 25% fly ash, 12% slag powder, and 0.5% flocculant. The water glass has a modulus of 2. The flocculant is metakaolin.

[0036] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The 5.61 tons of soft soil obtained after excavation were mixed with 4.27 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 35%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 7:4, and the ambient temperature of the area to be stabilized was 3°C.

[0037] Example 5 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to water glass is 3:1. The cementitious material comprises the following components by mass percentage: 54.5% silicate cement, 30% fly ash, 15% slag powder, and 0.5% flocculant. The water glass has a modulus of 2. The flocculant is a mixture of cellulose ether and polyethylene glycol diacrylate in a mass ratio of 1:1.

[0038] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The 5.82 tons of soft soil obtained after excavation were mixed with 3.88 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 40%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:3, and the ambient temperature of the area to be stabilized was 5°C.

[0039] Example 6 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to water glass is 4:1. The cementitious material comprises the following components by mass percentage: 64% silicate cement, 30% fly ash, 5% slag powder, and 1% flocculant. The water glass has a modulus of 3. The flocculant is a mixture of polyacrylamide and polyethylene glycol diacrylate in a mass ratio of 1:1.

[0040] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 4 meters. The 7.75 tons of soft soil obtained after excavation were mixed with 4.15 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 40%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 7:3, and the ambient temperature of the area to be stabilized was 5°C.

[0041] Example 7 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 4:1. The cementitious material comprises the following components by mass percentage: 66% silicate cement, 25% fly ash, 8% slag powder, and 1% flocculant. The water glass has a modulus of 3. The flocculant is a mixture of cellulose ether and metakaolin in a mass ratio of 1:1.

[0042] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 4 meters. The 8.03 tons of soft soil obtained after excavation were mixed with 5.02 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 45%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:3, and the ambient temperature of the area to be stabilized was 8°C.

[0043] Example 8 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to water glass is 4:1; the cementitious material comprises the following components by mass percentage: 69% silicate cement, 20% fly ash, 10% slag powder, and 1% flocculant. The water glass has a modulus of 3. The flocculant is polyacrylamide and metakaolin in a mass ratio of 1:1.

[0044] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 4 meters. The 8.03 tons of soft soil obtained after excavation were mixed with 4.3 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 45%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 7:3, and the ambient temperature of the area to be stabilized was 8°C.

[0045] Example 9 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to water glass is 4:1. The cementitious material comprises the following components by mass percentage: 72% silicate cement, 15% fly ash, 12% slag powder, and 1% flocculant. The water glass has a modulus of 3. The flocculant is a mixture of cellulose ether, polyacrylamide, and metakaolin in a mass ratio of 1:1:1.

[0046] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 4 meters. The 8.31 tons of soft soil obtained after excavation were mixed with 5.59 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 50%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 13:7, and the ambient temperature of the area to be stabilized was 10°C.

[0047] Example 10 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to water glass is 4:1. The cementitious material comprises the following components by mass percentage: 74% silicate cement, 10% fly ash, 15% slag powder, and 1% flocculant. The water glass has a modulus of 3. The flocculant is a mixture of cellulose ether, polyethylene glycol diacrylate, and metakaolin in a mass ratio of 1:1:1.

[0048] The low-temperature soil stabilizer of this embodiment was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 4 meters. The 8.31 tons of soft soil obtained after excavation were mixed with 5.59 tons of the low-temperature soil stabilizer of this embodiment, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 50%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 13:7, and the ambient temperature of the area to be stabilized was 10°C.

[0049] Comparative Example 1 No low-temperature soil stabilizer was used. Excavation was carried out in the same soft soil as in Example 1, with a depth of 3 meters. After backfilling, the soil was statically compacted twice with a 10-ton steel wheel roller and then leveled. Finally, it was vibrated three times with a 20-ton steel wheel roller. The soft soil had a moisture content of 30%, and the ambient temperature of the excavation area was 0°C.

[0050] Comparative Example 2 A low-temperature soil stabilizer comprises a cementitious material and water glass, wherein the mass ratio of the cementitious material to the water glass is 3:1. The cementitious material comprises the following components by mass percentage: 85% silicate cement, 10% fly ash, and 5% slag powder. The modulus of the water glass is 2. The flocculant is cellulose ether. The method for stabilizing soft soil using the above-mentioned low-temperature soil stabilizer in this comparative example is exactly the same as in Example 1.

[0051] Comparative Example 3 The low-temperature soil stabilizer in this comparative example is exactly the same as that in Example 1.

[0052] The low-temperature soil stabilizer described in this comparative example was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The resulting 5.19 tons of soft soil were mixed with 4.62 tons of the low-temperature soil stabilizer described in this comparative example, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, followed by three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil moisture content was 25%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 0℃.

[0053] Comparative Example 4 The low-temperature soil stabilizer in this comparative example is exactly the same as that in Example 1.

[0054] The low-temperature soil stabilizer described in this comparative example was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 3 meters. The resulting 6.44 tons of soft soil were mixed with 5.72 tons of the low-temperature soil stabilizer described in this comparative example, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled and then three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil had a moisture content of 55%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 0℃.

[0055] Comparative Example 5 The low-temperature soil stabilizer in this comparative example is exactly the same as that in Example 1.

[0056] The low-temperature soil stabilizer described in this comparative example was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 2 meters. The resulting 3.6 tons of soft soil were mixed with 3.2 tons of the low-temperature soil stabilizer described in this comparative example, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, followed by three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil moisture content was 30%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 0℃.

[0057] Comparative Example 6 The low-temperature soil stabilizer in this comparative example is exactly the same as that in Example 1.

[0058] The low-temperature soil stabilizer described in this comparative example was used to stabilize soft soil. Excavation was carried out in the area to be stabilized, with a depth of 5 meters. The resulting 9 tons of soft soil were mixed with 8 tons of the low-temperature soil stabilizer described in this comparative example, and then backfilled and stabilized. After two passes of static compaction with a 10-ton steel wheel roller, the soil was leveled, followed by three passes of vibratory compaction with a 20-ton steel wheel roller. The soft soil moisture content was 30%, the mass ratio of cementitious material in the soft soil to the low-temperature soil stabilizer was 6:4, and the ambient temperature of the area to be stabilized was 0℃.

[0059] Test Analysis Method Soil samples were taken from the soft soil solidification treatments of Examples 1-10 and Comparative Examples 1-6 above. The samples were then cured in a standard curing room at a temperature of 20±2℃ and a relative humidity of 95% or higher for a certain number of days, followed by the following performance tests: 1. Unconfined compressive strength: Soil samples after 28 days of standard curing were tested according to standard CJ / T486-2015.

[0060] 2. Freeze-thaw cycle performance test: Soil samples after 28 days of standard curing were soaked in water (20±2℃) for 24 hours, then frozen in a -18℃ freezer for 24 hours. The samples were then taken out and placed in a 20℃ constant temperature chamber for 24 hours. This was recorded as one freeze-thaw cycle. After five such cycles, the unconfined compressive strength was tested again, and the strength retention rate was calculated.

[0061] The performance test results of Examples 1-10 and Comparative Examples 1-6 are shown in Table 3.

[0062] Table 3 Performance Test Results

[0063] As can be seen from the performance test results in Table 3, the low-temperature soil stabilizer of this invention has low requirements for the construction environment temperature. Construction can be carried out as long as the ambient temperature is not lower than the freezing point. Even if the ambient temperature is at the freezing point, it can still significantly improve the freeze-thaw cycle resistance of soft soil and also has a certain effect on improving the compressive strength of soft soil, as shown in the following details: (1) As can be seen from the comparison between Example 1 and Comparative Example 1, the low-temperature soil stabilizer of the present invention can significantly improve the freeze-thaw cycle resistance of soft soil. The freeze-thaw cycle retention rate increased from 78.5% to 93.5%, and the compressive strength also increased from 6.5MPa to 7.4MPa. Even for soft soil with a water content of 30%, the low-temperature soil stabilizer of the present invention is significantly better than similar products on the market.

[0064] (2) Comparison of Examples 1 with Examples 2, 5, and 6 shows that although moisture content has a significant impact on the freeze-thaw cycle resistance of soft soil, it is still evident from the above examples that increasing the dosage of the low-temperature soil stabilizer of this invention can improve the freeze-thaw cycle resistance of soft soil. Analysis of a large amount of on-site sampling data reveals that mixing soft soil with the cementitious material in the low-temperature soil stabilizer of this invention at a mass ratio of (6~7):(4~3) produces the best freeze-thaw cycle resistance at the lowest cost. Even with a higher dosage of the low-temperature soil stabilizer of this invention, if the mass ratio of soft soil to the cementitious material in the low-temperature soil stabilizer is less than 6:4, the freeze-thaw cycle resistance of the soft soil will not improve significantly, and the freeze-thaw cycle retention rate has almost reached its maximum value. When the amount of the low-temperature soil stabilizer of the present invention is too low, the mass ratio of soft soil to cementitious material in the low-temperature soil stabilizer is higher than 7:3. At this time, the effect of the low-temperature soil stabilizer on improving the freeze-thaw cycle resistance of soft soil is not significant. Even if the low-temperature soil stabilizer of the present invention is used, the freeze-thaw cycle resistance of soft soil is still low.

[0065] (3) A comparison of Example 1 and Comparative Example 2 shows that the use of flocculant significantly improves the freeze-thaw cycle resistance of soft soil. Without the addition of flocculant, the freeze-thaw cycle retention rate of soft soil only increases by less than 3 points. Although the increase in water content of soft soil will significantly reduce its freeze-thaw cycle resistance, a comparison of Examples 1-5 and Examples 6-10 shows that the freeze-thaw cycle retention rate of Examples 6-10 is not significantly lower than that of Examples 1-5 due to the increase in the amount of flocculant used. Moreover, a comparison of Examples 5 and 6 shows that for soft soil with the same water content, although the amount of low-temperature soil stabilizer in Example 6 is less than that in Example 5, Example 6 maintains almost the same freeze-thaw cycle retention rate as Example 5 due to the increase in the amount of flocculant used. At the same time, through analysis of a large amount of on-site sampling data, this invention found that the effect of flocculant usage is only significant in the range of 0.5~1.0 wt%. Higher amounts of flocculant will lead to a reduction in the amount of silicate cement used, thereby worsening the solidification effect of soft soil. Therefore, once the flocculant dosage reaches 1 wt%, a higher flocculant dosage will actually lead to a decrease in freeze-thaw cycle resistance.

[0066] (4) As can be seen from the comparison between Example 1 and Comparative Examples 3 and 4, since the moisture content of soft soil directly affects its freeze-thaw cycle resistance, when the moisture content of soft soil is 25% (Comparative Example 3), its freeze-thaw cycle resistance is significantly improved compared to the soft soil with a moisture content of 30% in Example 1. Therefore, after using the low-temperature soil stabilizer of the present invention, the freeze-thaw cycle retention rate of the soft soil in Comparative Example 3 was not significantly improved compared to Example 1. When the moisture content of soft soil reaches 55%, its freeze-thaw cycle resistance has deteriorated severely. Even with the use of the low-temperature soil stabilizer of the present invention, its freeze-thaw cycle retention rate is still low, and the low-temperature soil stabilizer of the present invention has almost no improvement effect on the soft soil at this time. Therefore, through the analysis of a large amount of on-site sampling data, the present invention found that the low-temperature soil stabilizer of the present invention has the most significant effect on improving the freeze-thaw cycle resistance of soft soil with a moisture content of 30% to 50%.

[0067] (5) As can be seen from the comparison between Example 1 and Comparative Examples 5 and 6, the application of the low-temperature soil stabilizer of the present invention to soft soil at different excavation depths will also have a significant impact on the freeze-thaw cycle resistance of soft soil. When the excavation depth is shallow, only 2 meters (Comparative Example 5), the freeze-thaw cycle resistance of the surface soft soil is significantly improved compared to the soft soil at an excavation depth of 3 meters in Example 1. Therefore, the freeze-thaw cycle retention rate of the soft soil in Comparative Example 5 after using the low-temperature soil stabilizer of the present invention is not significantly improved compared to Example 1. When the excavation depth reaches 5 meters, the freeze-thaw cycle resistance of the deep soil is already very poor. Even with the use of the low-temperature soil stabilizer of the present invention, the freeze-thaw cycle retention rate is still low. The low-temperature soil stabilizer of the present invention has almost no improvement effect on the soft soil at this time. Therefore, through the analysis of a large amount of on-site sampling data, the present invention found that the low-temperature soil stabilizer of the present invention has the most significant improvement effect on the freeze-thaw cycle resistance of soft soil at an excavation depth of 3 to 4 meters.

[0068] In summary, the low-temperature soil stabilizer of this invention can significantly improve the freeze-thaw cycle resistance of soft soil, and also has a certain enhancing effect on the compressive strength of soft soil. Especially for soft soil with a moisture content of 30%~50%, by excavating to a depth of 3~4 meters and applying the low-temperature soil stabilizer at a mass ratio of (6~7):(4~3) of the cementitious material in the soft soil stabilizer, the soft soil strengthening effect of the low-temperature soil stabilizer of this invention can be maximized.

[0069] All materials used in this invention are commercially available and can be purchased from retail sources.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature soil stabilizer, characterized in that, The low-temperature soil stabilizer includes a cementing material and water glass, wherein the mass ratio of the cementing material to water glass is (3~4):1; The cementitious material comprises the following components by mass percentage: 54%~84.5% silicate cement, 10%~30% fly ash, 5%~15% slag powder, and 0.5%~1% flocculant.

2. The low-temperature soil stabilizer according to claim 1, characterized in that, The modulus of the water glass is 2 to 3.

3. The low-temperature soil stabilizer according to claim 1, characterized in that, The silicate cement is designated as PO.42.5 silicate cement.

4. The low-temperature soil stabilizer according to claim 1, characterized in that, The fly ash is classified as F1 fly ash.

5. The low-temperature soil stabilizer according to claim 1, characterized in that, The slag powder is S95 grade slag powder.

6. The low-temperature soil stabilizer according to claim 1, characterized in that, The flocculant includes at least one of cellulose ether, polyacrylamide, polyethylene glycol diacrylate, and metakaolin.

7. A construction method for a low-temperature soil stabilizer, characterized in that, The construction method includes: Excavation is carried out in the soft soil area to be solidified, and the depth of the excavation is 3 to 4 meters; The soft soil obtained after excavation is mixed with the low-temperature soil stabilizer described in any one of claims 1-6, and then backfilled and stabilized.

8. The construction method according to claim 7, characterized in that, The moisture content of the soft soil is 30% to 50%.

9. The construction method according to claim 7, characterized in that, The mass ratio of cementitious material in the soft soil and low-temperature soil stabilizer is (6~7):(4~3).

10. The construction method according to claim 7, characterized in that, The ambient temperature of the area to be cured is ≥0℃.

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