WO2021068235A1

WO2021068235A1 - High-strength curing agent application method for peat soil

Info

Publication number: WO2021068235A1
Application number: PCT/CN2019/110784
Authority: WO
Inventors: 潘弘杰
Original assignee: 潘弘杰
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2021-04-15

Abstract

A high-strength curing agent application method for peat soil, comprising the following steps: preprocessing construction waste, removing impurities and coarse aggregates, grinding, and selecting waste concrete muck having uniform particle size; crushing and sieving waste concrete and waste mortar to prepare construction waste muck having uniform particles the particle sizes of which are lower than 4.75 mm, and mixing the construction waste muck and peat soil according to a weight ratio; mixing the composite soil of the construction waste muck and the peat soil, portland cement, diatomaceous earth, sodium silicate, an excitant, an accelerator, and the like, then dissolving liquid glycerin in a certain amount of water, mixing uniformly, and adding to water to be used, and placing into a rotary spray device for subsequent use; and placing the mixture into a high-pressure rotary spray device, and after high-pressure rotary spraying, curing same naturally.

Description

Application method of high-strength curing agent suitable for peat soil

Technical field

The invention relates to the technical field of building materials, in particular, to an application method of a high-strength curing agent suitable for peat soil.

Background technique

The peat soil around Dianchi Lake is widely distributed, and it has a great impact on roads and buildings, causing many engineering accidents and threatening the lives and property of the people. As the urban roads around Kunming Dianchi Lake are built on peat soil, there are often a series of problems such as roadbed subsidence, surface cracking, and uneven road surface. Therefore, it is of great significance to develop a peat soil curing agent that can improve the mechanical properties of peat soil and to use this curing agent to reinforce the roadbed with jet-grouted piles.

At present, there are related literatures on peat soil curing agents and related results have been published.

Architectural Engineering Technology and Design, mid-February 2014, pages 519-521, "Research on Portland Cement-Soil Mixture Ratio of High Pressure Rotary Jetting Waterproof Curtain Piles in Kunming Peat Soil Area", studied the dephosphorization sodium silicate, silicon Test data and reaction mechanism of various ratios of algaeous earth and Portland cement added peat soil as curing agent for peat soil curing; Science Technology and Engineering, April 2012, Issue 11, Volume 12, 2768-2771 Page, in the article "Improvement of Mechanical Properties of Kunming Dianchi Peat Soil", not only the main components of Kunming Dianchi peat soil, but also the solidification of Portland cement, lime and sodium silicate with various ratios of curing agents are studied. effect.

The above curing agent uses Portland cement, lime, diatomaceous earth and sodium silicate as the main raw materials, but its curing cost is relatively high. In order to reduce the cost, it is necessary to add construction waste soil and further study the physical properties of the curing agent.

The construction waste soil used in the curing agent of the present invention refers to the waste concrete, fine sand, broken glass and the like generated during the demolition of urban villages in municipal planning and construction and the demolition of dilapidated and dilapidated houses. It belongs to the recycling and utilization of renewable resources, the raw materials are easily available, and the cost is low. This kind of construction waste soil and other components in the curing agent Portland cement, sodium silicate, diatomaceous earth, quick-setting agent, etc. are sprayed on the acid peat soil with large pores, low density, high moisture content, and high organic matter content. in. Portland cement is used as a gelling agent, and the construction waste soil not only acts as an aggregate, but also chemically reacts under the excitation of the activator. It quickly reacts with Portland cement hydrate and sodium silicate to produce expansive substances. Fill the pores of peat soil while consuming the water content of peat soil, compact the structure of peat soil, and increase the pH value of peat soil. Under the pressure of the surrounding peat soil, a pile foundation with better mechanical properties is formed. It is mainly used in the reinforcement of ordinary highways and rural roads with high demand for low-cost jet grouting piles.

Summary of the invention

The purpose of the present invention is to improve the mechanical properties and methods of peat soil soft soil, provide a curing agent used to strengthen peat soil roadbed and a method of using this curing agent to reinforce peat soil by means of jet grouting piles. Solve technical problems.

To achieve the above objective, the present invention provides a high-strength curing agent suitable for peat soil and an application method thereof.

An application method of a high-strength curing agent suitable for peat soil, the steps are as follows:

1) Pretreatment of construction waste, removal of debris, coarse aggregates, grinding powder, and then selection of waste concrete with uniform particle size;

2) Crushing and sieving waste concrete and waste mortar to obtain uniform particles of construction waste soil with a particle size of less than 4.75mm, and mix the construction waste soil and peat soil according to the weight ratio;

3) Mix the mixed soil of construction waste soil and peat soil, Portland cement, diatomaceous earth, sodium silicate, activator, accelerator, etc. according to the proportion, and then dissolve the liquid glycerin in a certain amount of water to mix Evenly add it to the water to be used, and put it into the rotary spray device for later use;

4) Put the above-mentioned mixture into a high-pressure rotary spraying device, and maintain it naturally after high-pressure rotary spraying.

A high-strength curing agent suitable for peat soil, including the following components by weight percentage: Portland cement 25-40%, glycerin 0.07-0.25%, diatomaceous earth 5-15%, sodium silicate 4-8%, Exciter 0.1-0.55%, quick-setting agent 1-5.5%, the balance of mixed soil of construction waste and peat soil.

Preferably, the stimulant is soda ash.

Preferably, the Portland cement is 42.5R or 42.5.

Preferably, in the mixed soil of construction waste soil and peat soil, construction waste soil accounts for 15-25%, and peat soil accounts for 75-85%.

1. Raw materials

Construction waste soil is the construction waste soil that is less than 4.75mm in particle size obtained by manual sorting, jaw crushing, grinding, vibrating screening and other processes from the reconstruction of urban villages. The main component is waste concrete fine particles. , Waste mortar. XRD diffraction analysis shows that more than 90% of the phase of waste construction residue is SiO2.

Portland cement is slag Portland Portland cement with a strength grade of 42.5. The 28-day compressive strength of Portland cement is 32.5Mpa. Portland cement is used as the cementing material of the curing agent. The quality of the curing agent plays a decisive role. Its main function is to wrap the surface of the waste sand particles and fill the pores between the sand particles; before the system sets and hardens, it acts as a lubricating material between the soil particles, which is conducive to uniform mixing. And block forming; in the process of pile foundation solidification and hardening, the cohesive force between the slag particles is strengthened, so that the solidified pile foundation can reach the required strength.

The accelerator is a high-efficiency accelerator of Tianyi brand sold by Kunming Jiasheng Concrete Admixture Sales Co., Ltd. The main component is alumina clinker (that is, clinker made from bauxite, soda ash and quicklime in proportion). Made by grinding finely. Accelerator can shorten the construction period, speed up the process of the project, and can also save the amount of portland cement in the project, which has good economic benefits. At the same time, it can also enhance the mechanical properties of solidified peat soil.

Soda ash, in the peat soil existing in diatomaceous earth and construction waste soil, can quickly dissolve in water and accelerate the pozzolanic reaction of diatomaceous earth and construction waste soil, and generate more cements to condense the peat soil residue particles to produce strength. Appropriate amount of soda ash, sodium silicate and Portland cement hydration reaction products produce needle-like ettringite; the formation of an ettringite structure consumes 31 water molecules, reducing the water content; the volume of the generated crystal water expands and fills the pores ; This will enable the pile foundation to have a more suitable micro-expansion on the basis of ensuring its strength and other good and stable properties, which can more effectively compensate for the shrinkage caused by water consumption and improve the mechanical properties of the pile foundation.

At present, the common domestic methods for peat ground treatment include shallow treatment, replacement, sand compaction, and deep mixing. The use of deep mixing and vibrating methods to treat peat soil foundations has caused many engineering accidents; the effect of powder injection pile technology to treat peat soil foundations is only used for foundation treatment with a long construction period; while gravel piles and powder injection piles are used for reinforcement Nankun Line Qidian peat soil subgrade can control the settlement of the subgrade; use Portland cement mixing piles to treat the peat soil foundation, increase the amount of Portland cement and change the construction method to meet the design and construction requirements; see Portland cement mixing piles The foundation treatment technology is not applicable to the peat soil reinforcement of Dianchi Lake. Foreign coastal countries such as the Netherlands and Norway in the Nordic countries have used jet-grouted pile Portland cement slurry to treat peaty soil foundations and achieved good results. However, due to the different formation conditions of peat soil, the use of traditional curing agents such as Portland cement, lime powder and other single curing materials to solidify peat soil can have a certain curing effect, but the peat soil has high water content and void ratio. The characteristics of large and rich organic matter, the actual strength of solidified peat soil is low, and the effect of solidifying peat soil by rotary spraying Portland cement slurry cannot meet the construction requirements.

The present invention uses rotary jet curing agent slurry to reinforce the peat soil foundation, which is to insert a grouting pipe with a special nozzle through a borehole to a predetermined depth for the treatment of the stratum, and then punch the soil body at high pressure with the slurry, and while spraying the slurry, Rotate and lift at a certain speed to form a cylinder of Portland cement soil. The jet grouting method has the advantage of being able to control the scope of reinforcement, making piles with a certain spacing, or connecting into one piece, and jet grouting into vertical piles, horizontal piles and inclined piles; in this way, as long as the amount of curing agent is appropriately adjusted, it can be used. According to different construction objects, solidified piles with corresponding mechanical properties can be obtained; the above-mentioned reinforcement can increase the bearing capacity of the foundation, reduce foundation settlement, piping and foundation pit uplift, and form an anti-seepage curtain. The technology of the present invention can be used as a temporary measure in construction, and can also be used as a permanent foundation reinforcement measure, which can meet different needs.

The present invention has the following beneficial effects: the solidifying agent of the present invention can be sprayed to reinforce peat soil by controlling the range of addition to form piles with a certain interval, or can be connected into one piece, and can be sprayed to form vertical piles, horizontal piles and piles. For inclined piles, the amount of curing agent is appropriately adjusted according to different construction objects to obtain piles with corresponding mechanical properties. It can be used as a temporary measure during construction or as a permanent foundation reinforcement measure.

In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The present invention will be described in further detail below.

Detailed ways

The following describes the embodiments of the present invention in detail, but the present invention can be implemented in a variety of different ways defined and covered by the claims.

Reinforce the peat soil foundation treatment with jet spray piles and solidification agent slurry. According to the "Technical Specification for Building Foundation Treatment" (JGJ 79-2012), based on different highway subgrade indicators, the solidification peat soil curing agent is designed with the help of uniform design software 3.0 For formula, refer to "Test Regulations for Inorganic Binder Stabilizing Materials for Highway Engineering" (JTGE51-2009), "Standard for Geotechnical Test Methods" (GB/T 50123-1999), "General Portland Portland Cement" (GB 175-2007) ).

Example 1

The high-strength curing agent suitable for peat soil includes the following components by weight percentage: Portland cement 37%, glycerin 0.13%, diatomaceous earth 12%, sodium silicate 6.5%, activator 0.2%, quick-setting 3%, the balance of mixed soil of construction waste and peat soil.

In the mixed soil of construction waste soil and peat soil, construction waste soil accounts for 20%, and peat soil accounts for 80%.

Example 2

The high-strength curing agent suitable for peat soil includes the following components by weight percentage: Portland cement 25%, glycerin 0.07%, diatomaceous earth 15%, sodium silicate 4%, activator 0.55%, quick-setting 1%, the balance of the mixed soil of construction waste residue and peat soil.

In the mixed soil of construction waste and peat soil, construction waste soil accounts for 25%, and peat soil accounts for 75%.

Example 3

1) Pre-treat construction waste, remove debris, coarse aggregates, grinding powder, and then select waste concrete with uniform particle size;

The high-strength curing agent suitable for peat soil includes the following components by weight percentage: Portland cement 40%, glycerin 0.25%, diatomaceous earth 5%, sodium silicate 8%, activator 0.1%, quick-setting Agent 5.5%, the balance of the mixed soil of construction waste and peat soil.

In the mixed soil of construction waste residue and peat soil, construction waste residue accounts for 15%, and peat soil accounts for 85%.

The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Anyone familiar with the technical field within the technical scope disclosed by the present invention, according to the technical solution of the present invention Equivalent replacements or changes to its inventive concept should all fall within the protection scope of the present invention.

Claims

An application method of a high-strength curing agent suitable for peat soil, which is characterized in that the steps are as follows:

1) Pretreatment of construction waste, removal of debris, coarse aggregates, grinding powder, and then selection of waste concrete with uniform particle size;

2) Crushing and sieving waste concrete and waste mortar to obtain uniform particles of construction waste soil with a particle size of less than 4.75mm, and mix the construction waste soil and peat soil according to the weight ratio;

3) Mix the mixed soil of construction waste soil and peat soil, Portland cement, diatomaceous earth, sodium silicate, activator, accelerator, etc. according to the proportion, and then dissolve the liquid glycerin in a certain amount of water to mix Evenly add it to the water to be used, and put it into the rotary spray device for later use;

4) Put the above-mentioned mixture into a high-pressure rotary spraying device, and maintain it naturally after high-pressure rotary spraying.
The application method of a high-strength curing agent suitable for peat soil according to claim 1, wherein the curing agent comprises the following components in weight percentage: 25-40% Portland cement, 0.07% glycerin -0.25%, diatomaceous earth 5-15%, sodium silicate 4-8%, activator 0.1-0.55%, quick-setting agent 1-5.5%, construction waste residue and peat soil mixed soil balance.
The application method of a high-strength curing agent suitable for peat soil according to claim 2, wherein the activating agent is soda ash.
The application method of a high-strength curing agent suitable for peat soil according to claim 2, wherein the Portland cement is 42.5R or 42.5.
The application method of a high-strength curing agent suitable for peat soil according to claim 2, wherein, in the mixed soil of construction waste soil and peat soil, construction waste soil accounts for 20% and peat soil accounts for 80%.
The application method of a high-strength curing agent suitable for peat soil according to claim 2, comprising the following ingredients in weight percentage: Portland cement 37%, glycerin 0.13%, diatomaceous earth 12%, sodium silicate 6.5 %, activator 0.2%, accelerator 3%, residual amount of mixed soil of construction waste and peat soil.