阅读说明：本技术 高液限软土直接用于预制装配式路基填筑材料的改良方法 (Improved method for directly applying high liquid limit soft soil to prefabricated assembly type roadbed filling material ) 是由 黄宝涛 朱汉华 张牧 黄保建 龚杰林 陈孟冲 周明妮 李家春 蒋儿 牛斌 朋茜 于 2019-11-19 设计创作，主要内容包括：本发明涉及一种高液限软土直接用于预制装配式路基填筑材料的改良方法,其特征在于,包括以下步骤：将高液限软土,按照顺序依次加入生石灰粉、低标号水泥、粉煤灰粉,然后按照加入顺序依次分别高速搅拌得到第一级初始混合料后进行初次闷料、按照顺序依次加入聚丙烯酸酯乳液、苯丙乳液、吸水树脂,进行二次闷料、再加入水稻秸秆、聚苯乙烯泡沫乳液、吸水树脂,进行三次闷料,最后,封装出符合道路填筑需要的封装块体,与现有技术相比,本发明的优点在于：本发明解决了利用高液限软土直接用于路基填筑问题,不仅实现本地资源的可循环利用,而且实现了填筑的预制装配化,提高了填筑路基的整体强度和承载能力。(The invention relates to an improved method for directly using high liquid limit soft soil for prefabricated roadbed filling materials, which is characterized by comprising the following steps: sequentially adding quicklime powder, low-grade cement and fly ash powder into high liquid limit soft soil in sequence, sequentially and respectively stirring at high speed according to the adding sequence to obtain a first-stage initial mixture, then carrying out primary material sealing, sequentially adding polyacrylate emulsion, styrene-acrylic emulsion and water-absorbent resin in sequence, carrying out secondary material sealing, adding rice straw, polystyrene foam emulsion and water-absorbent resin, carrying out tertiary material sealing, and finally packaging to obtain a packaging block meeting the road filling requirement. The invention solves the problem of directly using high liquid limit soft soil for roadbed filling, not only realizes the recycling of local resources, but also realizes the prefabrication and assembly of filling, and improves the overall strength and bearing capacity of the filled roadbed.)

1. An improved method for directly using high liquid limit soft soil for prefabricated roadbed filling materials is characterized by comprising the following steps:

a. sequentially adding quicklime powder, low-grade cement and fly ash powder into the high liquid limit soft soil in sequence, and then sequentially and respectively stirring at high speed according to the adding sequence to obtain a first-stage initial mixture;

b. b, standing and stacking the first-stage initial mixture obtained in the step a, and carrying out primary material sealing to obtain a first-stage final mixture;

c. b, sequentially adding the first-stage final-stage mixture obtained in the step b into polyacrylate emulsion, styrene-acrylic emulsion and water-absorbent resin in sequence, and sequentially and respectively stirring at high speed according to the adding sequence to obtain a second-stage initial mixture;

d. c, standing and stacking the second-stage initial mixture obtained in the step c, and carrying out secondary material sealing to obtain a second-stage final mixture;

e. d, adding rice straws into the second-stage final-stage mixture obtained in the step d, and stirring at a high speed, wherein the fiber content of the rice straws is 20-26%, and the length of the rice straws is 30-80 mm;

f. e, sequentially adding polystyrene foam emulsion prepared from styrene resin and a foaming agent and high-performance water-absorbent resin into the second-stage final-stage mixture obtained in the step e, and sequentially and respectively stirring at high speed according to the adding sequence to obtain a third-stage initial mixture;

g. d, standing and stacking the third-stage initial mixture obtained in the step f, and carrying out three-time material sealing to obtain a third-stage final mixture;

h. and g, filling the third-stage final mixture obtained in the step g into a packaging bag, and then carrying out pressurization, solidification and vacuum negative pressure packaging through a pressurization molding and vacuum thermoplastic packaging device to obtain a packaging block body meeting the road filling requirement.

2. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 1, wherein the method comprises the following steps: adding the quicklime powder in the step a according to the mass ratio of the quicklime powder to the high liquid limit soft soil of (14-20) to 100, and stirring;

adding the low-grade cement according to the mass ratio of the low-grade cement to the high liquid limit soft soil of (4-20):100, and stirring;

adding the fly ash powder according to the mass ratio of (6-15) to 100 of the fly ash powder to the high liquid limit soft soil, and stirring.

3. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 2, wherein the method comprises the following steps: adding the quicklime powder in the step a, and stirring for 2-5 min; adding low-grade cement and stirring for 2-3 min; and adding the fly ash powder, and stirring for 1-2 min to obtain a first-stage initial mixture.

4. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 1, wherein the method comprises the following steps: in the step c, the addition amount of the polyacrylate emulsion is added according to the mass ratio of (0.3-0.9) to 100 of the first-stage final-stage mixture, and then the mixture is stirred;

adding the styrene-acrylic emulsion according to the mass ratio of the styrene-acrylic emulsion to the first-stage final-grade mixture of (0.3-0.9) to 100, and stirring;

the addition amount of the water-absorbing resin is added according to the mass ratio of (0.1-0.9) to 100 of the first-stage and final-stage mixed materials, and then the mixture is stirred.

5. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 4, wherein the method comprises the following steps: adding the polyacrylate emulsion in the step c, and stirring for 3-5 min; adding the styrene-acrylic emulsion and stirring for 2-5 min; and adding the water-absorbent resin, and stirring for 2-6 min.

6. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 1, wherein the method comprises the following steps: in the step e, the adding amount of the rice straws is (0.005-0.03) according to the total amount ratio of the rice straws to the second-stage final-grade mixed material: 100 and stirred.

7. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 1, wherein the method comprises the following steps: in the step f, the addition amount of the polystyrene foam emulsion is (0.3-0.9) according to the volume ratio of the polystyrene foam emulsion to the second-stage final-grade mixed material: adding the mixture according to the proportion of 100 and stirring;

the addition amount of the high-performance water-absorbing resin is (0.2-0.5) according to the volume ratio of the high-performance water-absorbing resin to the second-stage final-stage mixed material: 100 and stirred.

8. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 7, wherein the method comprises the following steps: adding the polystyrene foam emulsion in the step f, and stirring for 3-5 min; and adding the high-performance water-absorbent resin, and stirring for 2-3 min.

9. The improved method of using high liquid limit soft soil directly in prefabricated roadbed filling material according to claim 1, wherein the method comprises the following steps: and d, standing, stacking and primary material sealing the primary mixture in the step b for 2-5 hours, standing, stacking and secondary material sealing the secondary primary mixture in the step d for 10-30 minutes, and standing, stacking and tertiary material sealing the tertiary primary mixture in the step g for 10-30 minutes.

10. The improved method for directly using high liquid limit soft soil in prefabricated roadbed filling materials according to any one of claims 1 to 9, wherein the method comprises the following steps: the packaging block body is in a cross shape.

Technical Field

The invention belongs to the technical field of highway and urban road construction, and particularly relates to an improvement method for directly using natural high liquid limit soft soil for a prefabricated roadbed filling material.

Background

The landform of the Yangtze river delta area in the Yangtze river both banks, Ningshao plain, the Jianghuai plain in the east of China and the Zhujiang river triangle area in the south of China is the sea area plain, the cover layer is mostly high liquid limit soft soil such as silt, high liquid limit soft soil, cohesive soil and the like, and is additionally provided with poor soil (saline soil, soft soil, expansive soil and high liquid limit soft soil) with a wide inland distribution range, and the high liquid limit soft soil (namely, three types of soft soil such as argillaceous clay, silt and silt sandy soil with the main body of which is more than 50% of the liquid limit and more than 26% of the liquid limit in highway engineering) and the poor soil can not be directly used in the construction of the highway engineering usually, or need to be changed and filled, or need to be processed by complicated improvement programs, so that the engineering cost is continuously increased. The current road can be divided into a plurality of structural levels according to the technical standards and construction specifications of highway engineering, and the common road can be divided into a surface layer, a base layer, a subbase layer and a roadbed from top to bottom, wherein the surface layer is directly contacted with the atmosphere, vehicles and pedestrians, and high strength, rigidity, flatness, skid resistance, wear resistance and the like are required. The base layer and the sub-base layer are main bearing structures of the road and play an important role in bearing tensile stress, the roadbed is a layer directly contacted with the soil foundation, and a good roadbed structure has stable characteristics and can adapt to deformation to a certain degree, so that the long-term use performance of the pavement structure is guaranteed. The technical measures adopted at present are to mix inorganic curing materials and coarse-grained soil for improvement, wherein the inorganic curing materials (quicklime or cement) or the coarse-grained soil are adopted for improvement, the construction process is not easy to control, the construction period is prolonged, the engineering cost is greatly increased, meanwhile, the construction of roadbed filling engineering mainly adopts paving, rolling and maintenance with optimal water content to reach the target compaction degree as a control index, on one hand, the defects of long construction period, large construction period influence by environment, easy environmental pollution and the like also exist, on the other hand, the engineering problem of the filled roadbed is prominent due to uneven settlement and the like because the difference of the filling of the roadbed is not effectively controlled and improved by the conventional high liquid limit soft soil improvement technology, and the problem is urgently needed to be solved by highway engineering technicians.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art and provides an improved method for directly using high liquid limit soft soil for prefabricated roadbed filling materials, which can improve the overall strength and bearing capacity of a filled roadbed and can effectively control differential settlement.

The technical scheme adopted by the invention for solving the technical problems is as follows: the improvement method for directly using the high liquid limit soft soil for the prefabricated roadbed filling material is characterized by comprising the following steps:

a. sequentially adding quicklime powder, low-grade cement and fly ash powder into the high liquid limit soft soil in sequence, and then sequentially and respectively stirring at high speed according to the adding sequence to obtain a first-stage initial mixture;

b. b, standing and stacking the first-stage initial mixture obtained in the step a, and carrying out primary material sealing to obtain a first-stage final mixture;

c. b, sequentially adding the first-stage final-stage mixture obtained in the step b into polyacrylate emulsion, styrene-acrylic emulsion and water-absorbent resin in sequence, and sequentially and respectively stirring at high speed according to the adding sequence to obtain a second-stage initial mixture;

d. c, standing and stacking the second-stage initial mixture obtained in the step c, and carrying out secondary material sealing to obtain a second-stage final mixture;

e. d, adding rice straws into the second-stage final-stage mixture obtained in the step d, and stirring at a high speed, wherein the fiber content of the rice straws is 20-26%, and the length of the rice straws is 30-80 mm;

f. e, sequentially adding polystyrene foam emulsion and high-performance water-absorbent resin which are prepared by regulating styrene resin and foaming agent into the second-stage final-stage mixture obtained in the step e, and sequentially and respectively stirring at high speed according to the adding sequence to obtain a third-stage initial mixture;

g. d, standing and stacking the third-stage initial mixture obtained in the step f, and carrying out three-time material sealing to obtain a third-stage final mixture;

h. and g, filling the third-stage final mixture obtained in the step g into a packaging bag, and then carrying out pressurization, solidification and vacuum negative pressure packaging through a pressurization molding and vacuum thermoplastic packaging device to obtain a packaging block body meeting the road filling requirement.

Further, the adding amount of the quicklime powder in the step a is added according to the mass ratio of the quicklime powder to the high liquid limit soft soil of (14-20):100, and then the mixture is stirred;

adding the low-grade cement according to the mass ratio of the low-grade cement to the high liquid limit soft soil of (4-20):100, and stirring;

adding the fly ash powder according to the mass ratio of (6-15) to 100 of the fly ash powder to the high liquid limit soft soil, and stirring.

In order to reduce the water content of the high liquid limit soft soil, preferably, the quicklime powder is added and stirred for 2-5% in the step amin; adding low-grade cement and stirring for 2-3 min; and adding the fly ash powder, and stirring for 1-2 min to obtain a first-stage initial mixture. The water of the soft soil with high liquid limit reacts with quicklime powder, low-grade cement and fly ash powder in a series of physical and chemical reactions to generate Ca (OH)₂，CaCO₃And hydrated calcium silicate, hydrated calcium sulphoaluminate (ettringite) and other mixtures, thereby increasing the soil body connection of the high liquid limit soft soil.

In order to further reduce the water content of the high liquid limit soft soil, the addition amount of the polyacrylate emulsion in the step c is preferably added according to the mass ratio of (0.3-0.9) to 100 of the first-stage and final-stage mixed materials, and then the mixture is stirred;

adding the styrene-acrylic emulsion according to the mass ratio of the styrene-acrylic emulsion to the first-stage final-grade mixture of (0.3-0.9) to 100, and stirring;

the addition amount of the water-absorbing resin is added according to the mass ratio of (0.1-0.9) to 100 of the first-stage and final-stage mixed materials, and then the mixture is stirred.

The polyacrylic ester emulsion, the styrene-acrylic emulsion and the water-absorbent resin reduce the thickness of a double-ionized-layer water film and the water absorption effect caused by pores and surface tension of the high-liquid-limit soft soil mainly through the actions of ion exchange, chemical polymerization reaction and the like, and then are stirred at a high speed to release more free water so as to form the high-liquid-limit soft soil particles with the further reduced distance between soil particles.

In order to promote the added organic polymer material to sufficiently reduce the electric polarity of the high liquid limit soft soil particles and promote the soil particles to sufficiently release the adsorbed water, preferably, the polyacrylate emulsion is added in the step c and then stirred for 3-5 min; adding the styrene-acrylic emulsion and stirring for 2-5 min; and adding the water-absorbent resin, and stirring for 2-6 min.

For the purpose of bridging and reinforcing water-absorbing clusters in the high liquid limit soft soil particles, preferably, the addition amount of the rice straws in the step e is (0.005-0.03) according to the mass ratio of the rice straws to the second-stage final-grade mixed material: 100 and stirred.

Wherein, this rice straw is for playing bridging and the effect of muscle that adds, and fibre length needs tens of or hundreds of soil particles of bridging to inhale aquatic ball to the reason that the length of injecing rice straw is 30mm-80mm lies in: the minimum length of the rice straw is 30mm, if the minimum length is less than 30mm, the purpose of bridging reinforcement cannot be achieved due to the fact that the rice straw is too short, and the maximum length of fibers is 100mm because the filling thickness of a road base layer is 3.0 times of the maximum particle size of a road base filling material and is generally 30cm, and the maximum length of the fibers is 80mm, and the fiber content of the rice straw is selected within 20% -26%: the fiber contained in the rice straw can effectively improve the strength of the high liquid limit soft soil, mainly because the randomly dispersed fiber is distributed in the high liquid limit soft soil particles in a net shape, the stress concentration of the high liquid limit soil can be borne under the friction action and the cementing action of the soil particles and cement hydrate, the larger the fiber mixing amount is, the larger the tensile stress can be borne, the stronger the load transfer and dispersion capacity is, in addition, the rice straw is composed of the 20-26% of fiber, plant protein, active silicon and other substances, and the anaerobic fermentation process is carried out in the next third material covering process, namely the anaerobic fermentation process, namely the process of absorbing water by the plant protein of the rice straw and solidifying the soft soil particles, so that the connection among the high liquid limit soft soil particles and the water absorbing resin particle clusters is further increased.

Further, in step f, the addition amount of the polystyrene foam emulsion is (0.3-0.9) according to the volume ratio of the polystyrene foam emulsion to the second-stage final-grade mixed material: adding the mixture according to the proportion of 100 and stirring;

the addition amount of the high-performance water-absorbing resin is (0.2-0.5) according to the volume ratio of the high-performance water-absorbing resin to the second-stage final-stage mixed material: 100 and stirred. The polystyrene foam emulsion promotes the self-coagulation of the soil particles, and the high-performance water-absorbent resin has extremely strong water absorbability and water retentivity, can convert a large amount of free water in the high-liquid-limit soft soil particles into water hydrate and absorbed water and stably exists in the water-absorbent resin, so that the connection among the high-liquid-limit soft soil particles is increased, and the strength of the high-liquid-limit soft soil is improved.

Further, adding the polystyrene foam emulsion in the step f, and stirring for 3-5 min; and adding the high-performance water-absorbent resin, and stirring for 2-3 min. Wherein, the selection of the water-absorbing resin needs to satisfy the following requirements: and finishing the whole process of water absorption and water fixation within the stirring time of 2-3 min.

Further, the time for carrying out standing stacking and primary material sealing on the first-stage initial mixture in the step b is 2-5 hours, the time for carrying out secondary material sealing on the second-stage initial mixture in the step d is 10-30 minutes, and the time for carrying out secondary material sealing on the third-stage initial mixture in the step g is 10-30 minutes. The primary material sealing, the secondary material sealing and the tertiary material sealing have the functions of promoting the high liquid limit soft soil and the modifier to have a series of physical, chemical, physical and chemical reactions, and the like, and rain-proof measures are taken in a factory during the material sealing period to prevent the water content of the high liquid limit soft soil from being increased due to rainwater.

Furthermore, the packaging block body is in a cross shape. In order to facilitate the packaging blocks to meet the requirements of different filling heights of roads, the improved high liquid limit soft soil can be packaged into cross-shaped mortise and tenon blocks with different compaction degrees, such as a packaging block with 93% compaction degree of a lower road bed, a packaging block with 95% compaction degree of an upper road bed, a packaging block with 97% compaction degree under a pavement structure layer and a light packaging block of a bridge head buffer area. Meanwhile, the packaging blocks are in a cross shape and can be spliced with each other to form a required filling roadbed which is convenient to pave.

Compared with the prior art, the invention has the advantages that: according to the characteristics of the high liquid limit soft soil, proper corresponding functional components are selected from the angles of promoting cement hydrated gel to coagulate and harden, thinning double electric layers, converting and adsorbing water macromolecules and the like respectively; ca (OH) produced by reaction of quicklime with water₂The high-concentration alkaline environment is formed to promote the cement hardening reaction, the polystyrene foam emulsion promotes the self-coagulation of soil particles, and the soil particles are stirredThe water-absorbent resin has strong water absorbability and water retentivity, can convert a large amount of redundant free water in the high liquid limit soft soil into bound water and absorbed water, and stably exists in the water-absorbent resin, in addition, the added rice straws can increase the connection among the high liquid limit soft soil particles and the water-absorbent resin particle clusters, and the tenon-and-mortise packaging bag and the vacuum packaging provide 360-degree confining pressure constraint of a soil body, so that the stability and the strength of the high liquid limit soft soil are improved; the invention solves the problem that high liquid limit soft soil is directly used for roadbed filling, not only realizes the recycling of local resources, but also improves the overall strength and bearing capacity of the filled roadbed, effectively controls differential settlement, realizes the coordination control problem of material deformation in roadbed filling, and solves the engineering problems of insufficient roadbed stability and easy occurrence of pavement cracking in the prior art.

Drawings

FIG. 1 is a flow chart of an improved method of using high liquid limit soft soil directly in prefabricating an assembled roadbed filling material in an embodiment of the invention;

fig. 2 is a schematic structural diagram of a package block in an embodiment of the invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.