Preparation method for backfilling fertilizer groove by in-situ soil solidification and fluid soil solidification

Abstract

The invention belongs to the technical field of soil solidification, and particularly relates to a preparation method for backfilling a fertilizer groove by in-situ soil solidification and fluid soil solidification, an in-situ soil solidification agent comprises ordinary Portland cement, mineral powder, calcium oxide, stone powder, an exciting agent and slag powder; the formula comprises the following components in percentage by mass: 30-70% of ordinary Portland cement, 25-60% of mineral powder, 10-15% of calcium oxide and 20-35% of stone powder. Aiming at the problems that the current solidified soft soil is easy to disperse, collapse and the like and even possibly has the problem of solidification reversion, industrial wastes are adopted as main raw materials and are compounded with other components to generate a synergistic effect. Under the condition of normal temperature, the composite materials can be tightly combined with soft soil particles with high water content, so that the physical and mechanical properties of the soft soil with high water content are remarkably improved. According to the method, the strength and integrity of the foundation can be rapidly enhanced, meanwhile, the strength after curing is high, the construction speed is high, the construction period is short, and the construction cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of soil solidification, and in particular relates to a preparation method for in-situ soil solidification and fluidized soil solidification for backfilling a fertilizer tank. Background Art

[0002] In China, urban road construction and backfilling of infrastructure and pipelines usually adopt traditional construction methods, that is, the excavated soil is transported to a designated spoil site. When encountering a thicker underground soft soil layer, the soft soil must be replaced. Because the soft soil layer in some areas is particularly thick, these areas need to be specially treated. However, the anti-permeability of mortar is not ideal and the cost is high, so it is not suitable for replacing thicker soft soil layers. This practice has led to the extension of the entire project cycle and generated significant dust and noise pollution during earthwork transportation, while increasing carbon dioxide emissions and aggravating road congestion. These factors have greatly affected people's quality of life and increased costs. After half a year to a year of use, roads and pipelines in many cities have various problems due to foundation subsidence and road inequality.

[0003] These special physical properties lead to low strength, high sensitivity, low bearing capacity, large uneven settlement, poor engineering properties, and easy to cause building sliding, collapse, tilt, etc. Therefore, before the construction of the superstructure, it is necessary to strengthen it to meet the requirements of bearing capacity and settlement control so that it can achieve the basic performance required for engineering construction.

[0004] At present, the application of soft soil and soil in-situ solidification technology in urban road, highway construction and pipeline backfilling operations is increasing, playing an increasingly critical role. However, the curing agents relied on by this technology, such as cement, slag powder, calcium oxide and stone powder, are mainly traditional curing materials. The production of cement not only continues to consume precious limestone and clay resources, but also is accompanied by huge energy consumption, causing significant negative impacts on the environment. At the same time, most new environmentally friendly soft soil curing agents need to be imported from abroad, which has led to a significant increase in product costs.

[0005] With the advancement of industrialization, various types of industrial waste have posed a serious threat to the environment on which human beings depend for survival. Converting these wastes, such as industrial slag, into sludge solidifiers is one of the key ways to realize the resource utilization of solid waste. However, due to the unique physical and chemical properties of soft soil, the soft soil solidification materials currently made from industrial waste have a significant defect: the solidified soft soil is prone to dispersion and collapse, and the solidification effect may even be reversed, which brings potential serious risks to subsequent construction.

[0006] To address these challenges, we have taken a series of improvement measures. Summary of the invention

[0007] To solve the problems raised in the above background technology, the present invention provides a preparation method and an improver for in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks, which is specially used for soft soil solidification to solve the problems and shortcomings in the prior art.

[0008] To achieve the above object, the present invention provides the following technical solutions: a preparation method for in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks, wherein the in-situ soil solidifier comprises ordinary Portland cement, mineral powder, calcium oxide, stone powder, activator, and slag powder;

[0009] The formula includes 30-70% of ordinary Portland cement, 25-60% of mineral powder, 10%-15% of calcium oxide, 20%-35% of stone powder and 1.5%-5% of activator by mass percentage.

[0010] Preferably, the formula of the improver consists of the following ingredients, expressed in mass percentage: 30-70% of ordinary Portland cement, 25-40% of mineral powder, 5-10% of calcium oxide, 15-25% of stone powder, and 2-5% of activator.

[0011] Preferably, the chemical composition of the mineral powder includes the following: Silicon dioxide (SiO2) usually accounts for 30-40%.

[0012] Preferably, aluminum oxide (Al2O3) usually accounts for 7-15%; calcium oxide (CaO) usually accounts for 40-50%; magnesium oxide (MgO) usually accounts for 1-10%; sulfur trioxide (SO3) usually accounts for 0.5-2.5%; other components, such as iron oxide (Fe2O3), potassium oxide (K2O), sodium oxide (Na2O), etc., usually account for 0.5-5%.

[0013] Preferably, the activator comprises the following components in percentage by mass: 10-15% calcium aluminate, 25-30% sodium silicate, 1-2% high molecular polymer, and 5-8% magnesium oxide.

[0014] Preferably, the specific surface area of ​​the soft soil solidifying agent powder is between 300 and 400 square meters per kilogram, the powder density ranges from 1.7 to 2.0 grams per cubic centimeter, and the standard consistency of the powder is 24% to 26%.

[0015] The beneficial effects of the present invention are as follows: in view of the problem that currently solidified soft soil is prone to dispersion, collapse, and even solidification reversal, the present invention uses industrial waste as the main raw material and compounds it with other components to produce a synergistic effect. Under normal temperature conditions, these composite materials can be tightly combined with soft soil particles with high water content, significantly improving the physical and mechanical properties of high water content soft soil. This method can quickly enhance the strength and integrity of the foundation, and at the same time, the strength after solidification is high, the construction speed is fast, the construction period is short, and the construction cost is low.

[0016] In addition, the curing agent of the present invention uses a large amount of industrial solid waste such as slag powder, calcium oxide and stone powder, and uses local materials as a new curing material to replace traditional cement. This not only greatly reduces the amount of cement used and reduces energy consumption, but also realizes the resource utilization of industrial solid waste and effectively reduces the negative impact of solid waste on the environment.

[0017] In summary, this curing agent has significant economic, social and environmental benefits and has broad application prospects. DETAILED DESCRIPTION

[0018] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0019] Example 1

[0020] The invention provides the following technical scheme: ordinary silicate cement accounts for 50%, slag powder accounts for 25%, stone powder accounts for 10%, calcium oxide powder accounts for 10%, and activator accounts for 5%.

[0021] The composition of the activator, calculated by mass percentage, includes 10-15% of calcium aluminate, 25-30% of sodium silicate, 1-2% of high molecular polymer, and 5-8% of magnesium oxide.

[0022] The powder specific surface area of ​​the soft soil solidifying agent is 300-400 square meters per kilogram, the powder density is 1.8-2 grams per cubic centimeter, and the standard consistency is 15-20%.

[0023] The curing agent of the present invention has a significant difference in the mechanism of action from traditional curing agents such as cement and lime or their mixtures. The uniqueness of the present invention is that the present invention is mainly composed of industrial waste materials, and although it contains abundant potential active materials, its natural hydration rate is quite slow. The activator in the present invention can quickly consume the water in the sludge and release heat, causing the sludge temperature to rise, thereby accelerating the hydration process of the potential active materials and promoting a significant increase in the early strength of the solidified sludge.

[0024] Mainly reflected in:

[0025] When the sludge is mixed with the curing agent, first, the high molecular polymer in it acts as an activator and rapidly hydrolyzes, consuming a large amount of water in the sludge, thereby reducing the moisture content of the soft soil. At the same time, the flocculation effect of the high molecular polymer causes the suspended particles in the sludge to aggregate and form a network structure, laying a solid foundation for the subsequent curing and strength improvement of the soft soil particles.

[0026] In the activator, calcium oxide is converted into high-valent metal ions and hydroxide (OH-) ions through hydrolysis, thus creating an alkaline environment. This environment is essential to ensure the stability of the cement hydration product, silica gel. At the same time, calcium oxide also reacts with alkali-active materials such as silicon oxide and aluminum oxide in slag powder to produce hydraulic cementitious products and other hydration products. These products can not only effectively reduce the moisture content of soft soil and fill the pores of the soil, but also show strong physical bonding ability. They can tightly wrap and connect soil particles, and continuously bond and harden, and finally bond the fluid high-water content soft soil into a structure with a certain strength.

[0027] In soft soil, the consumption of water and the cementation between particles will lead to the formation of a large number of pores. At this time, sodium silicate, as an activator, reacts with the high-valent metal ions in the pore water to generate calcium silicate or silica gel particles. These newly generated particles further fill the gaps between the soft soil particles, thereby enhancing the compactness of the soft soil structure and improving its strength.

[0028] Calcium chloride, as an activator, can significantly accelerate the hydration reaction rate of tricalcium aluminate and stimulate the activity of slag powder. It has the effect of promoting coagulation and early strength enhancement, thereby improving the initial strength of solidified soft soil and effectively preventing the dispersion and collapse of early solidified soil.

[0029] In this embodiment, the ratio used is 50% of PO42.5 ordinary Portland cement, 25% of slag powder, 10% of stone powder, 10% of calcium oxide powder, and the activator includes 10-15% of calcium aluminate, 25-30% of sodium silicate, 1-2% of high molecular polymer and 5-8% of magnesium oxide. After mixing the materials, ensure that 5% of the ingredients are evenly distributed. During storage and transportation, strict moisture-proof measures must be implemented.

[0030] The product of Example 1 was used to solidify the Dongsheng Service Area of ​​Zhongjiang Expansion in Zhongshan, Guangdong. The moisture content of the soft soil was 85%, and the amount of curing agent added was 8% of the dry weight of the soft soil. After the curing agent and the soft soil were fully stirred and mixed, natural curing was carried out. After 7 days of curing, the unconfined compressive strength of the solidified soft soil reached 0.8MPa; after 28 days, the unconfined compressive strength was further increased to 1.8MPa. In addition, the solidified soft soil did not show problems such as dispersion and collapse, and there was no settlement phenomenon.

[0031] Example 2

[0032] An additive for solidifying soft soil, the formula ratio of which is calculated by weight percentage, including 40% of PO42.5 grade ordinary Portland cement, 35% of slag powder, 15% of stone powder, 5% of calcium oxide powder, and an activator containing 10-15% of calcium aluminate, 25-30% of sodium silicate, 1-2% of high molecular polymer and 5-8% of magnesium oxide. After mixing the above materials, it is necessary to ensure that 5% of the ingredients are evenly distributed. During storage and transportation, strict moisture-proof measures must be taken.

[0033] The product of Example 2 was used to solidify the soft soil in the project area of ​​Zhongshan Science City, Guangdong. The soft soil had a moisture content of 95% and the amount of curing agent added was 12% of the dry weight of the soft soil. After the curing agent and the soft soil were fully stirred and mixed, natural curing was carried out. After 7 days of curing, the unconfined compressive strength of the solidified soft soil reached 1.3MPa, and after 28 days, its unconfined compressive strength was increased to 2.7MPa. In addition, the solidified silt soil did not have problems such as dispersion and collapse.

[0034] Example 3

[0035] A curing agent for curing soft soil, the ingredients of which are as follows: 55% of PO42.5 grade ordinary Portland cement, 25% of slag powder, 10% of stone powder and 5% of calcium oxide powder. As for the activator, it is composed of 10-15% of calcium aluminate, 25-30% of sodium silicate, 1-2% of high molecular polymer and 5-8% of magnesium oxide. When mixing the materials, it is necessary to ensure that the 8% ingredients are evenly distributed. During the storage and transportation of the materials, strict moisture-proof measures must be taken.

[0036] The product described in Example 3 was used to solidify the Hezhong Road project in Zhongshan, Guangdong, where the initial moisture content of the sludge was 100%. The amount of curing agent added was 16% of the dry weight of the soft soil. After the curing agent and the soft soil were thoroughly mixed and stirred, natural curing was carried out. After 7 days of curing, the average unconfined compressive strength of the solidified soft soil reached 2.6MPa; and after 28 days, the strength was further increased to 6MPa. In addition, the solidified silt soil solved the problems of dispersion and collapse.

[0037] The above describes in detail the specific embodiments of the present invention, but the scope of the present invention is not limited to these examples. As long as the basic purpose of the present invention is not deviated from, the present invention can have many different variations.

[0038] Specifically, the in-situ soil solidification technology of the present invention is applicable to the backfilling of soil in the foundation of urban roads and fertilizer troughs under roads. After in-situ solidification using the curing agent of the present invention, the soil can meet the strength requirements of the road foundation three-in-one soil, with low cost, and its life cycle far exceeds that of traditional three-in-one soil, and has excellent stress release performance. The solidified soil not only has the strength and flexural resistance of three-in-one soil, but is also superior to three-in-one soil in some aspects.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks, characterized in that: In-situ soil stabilizers include ordinary Portland cement, mineral powder, calcium oxide, stone powder, activator, and slag powder; The formula includes 30-70% of ordinary Portland cement, 25-60% of mineral powder, 10%-15% of calcium oxide, 20%-35% of stone powder and 1.5%-5% of activator by mass percentage.

2. The preparation method of in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks according to claim 1, characterized in that: The chemical components of the mineral powder include: SiO2, Al2O3, CaO, MgO, Fe2O3, TiO2 and MnO2.

3. The preparation method of in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks according to claim 1, characterized in that: The slag powder has a moisture content of 1%-4%, and the chemical composition of the slag powder is 30-45% of calcium oxide and 55-70% of stone powder.

4. The preparation method of in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks according to claim 1, characterized in that: The activator comprises, by mass percentage, 10-15% of calcium aluminate, 46-66% of sodium silicate, 16-27% of calcium chloride and 1-7% of high molecular polymer.

5. The preparation method of in-situ soil solidification and fluidized soil solidification for backfilling fertilizer tanks according to claim 1, characterized in that: The powder specific surface area of ​​the in-situ soil solidifying agent is 300-400%, the powder density of the in-situ soil solidifying agent is 1.7-2.2 g / cm3, and the powder standard consistency of the in-situ soil solidifying agent is 13-20%.