CN100513701C

CN100513701C - Method for solidifying beach salty soil

Info

Publication number: CN100513701C
Application number: CNB2007100575244A
Authority: CN
Inventors: 柴寿喜
Original assignee: Tianjin Urban Construction College
Current assignee: Tianjin Urban Construction College
Priority date: 2007-06-04
Filing date: 2007-06-04
Publication date: 2009-07-15
Anticipated expiration: 2027-06-04
Also published as: CN101100855A

Abstract

A solidify method for salty soil near beach includes steps as: spray water to the soil to make water content 3-5% lower than the best value; evenly broadcast 8% calces on the soil and mixing; spray a water solution of 4% SH soil solidify agent to the mixed soil and mixing again; smooth the ground and roll once by a 20T roller and vibrate twice, roll once again.

Description

A kind of method of solidifying beach salty soil

Technical field

The present invention relates to a kind of method of solidifying beach salty soil, particularly by the method for optimum mix proportion and on-site rolling beach salty soil is carried out modified solidified method, belong to soil body modified reinforcing and field tests with solid native agent of SH and quicklime.

Background technology

Beach salty soil is a kind of special soil that is fine particulate, the lyotropic salt that contains 0.3%-3%, wherein sodium chloride accounts for the overwhelming majority, have that strong salt expands, moltenly falls into, bad engineering propertiess such as corrosivity and the moisture absorption property of softening, be in particular in the molten sunken sedimentation of soil layer, the swelling cracking and the softening problem of moisture absorption of soil layer.The strong capillarity of the native high salinity in beach salty soil area, phreatic high and fine grained soil, the suction that all causes solidifying beach salty soil easily is softening, the primary geotechnical engineering problems that becomes in the bad engineering properties of beach salty soil is softened in suction, affects the stability and the durability of building lot or road embankment for many years always.How research expand salt, molten fall into and moisture absorption is softening etc. that problem is controlled in the engineering permissible range, and keep modified solidified soil to have certain water stability and durability in the operating period in engineering, very necessary to safety and the durability that improves building lot or embankment.

The liquid macromolecule organic material that the solid native agent of SH is Lanzhou University's exploitation, cheap, nontoxic pollution-free.Its molecular weight is about 20,000, and solid content is 6%.Hydrophilic radical is arranged on its macromolecular chain: hydroxyl, carboxyl etc., its main chain is the macromolecular chain that hydrophobicity C-the C key links.But meet the water infinite dilution, viscosity is low, gel time is easy to control, has good physical and mechanical property and broad service condition.After being spiked into the solid native agent of SH in the soil, irreversible physical-chemical reaction can take place with soil in it, dry back solidified earth is hardened condition, though meet macromolecular material colloid deliquescing behind the water once more, but no longer dissolving, and keep good toughness, and soil particle is tightened together, improved the water stability and the durability of solidified earth.

Wang Yinmei once carried out research (" rock mechanics " the 25th volume o. 11th to the solid native agent Stabilization of Loess mechanical property of SH, novel high polymer curing materials and the comparative study of cement stabilization loess mechanical property), the volume of selecting the solid native agent of SH for use is that 0.63%-1.35% of solidfied material quality is solidified loess, and has finished resistance to compression, compression, infiltration, water resistance, frost resistance, test such as ageing-resistant.The sample of 60d curing age, the addition content of the solid native agent of SH is 1.25%, and compressive strength is brought up to the 5.04MPa of solidified earth by the 2.29MPa of plain loess, and intensity improves about 100%.The Wang Yin plum also with directly spraying at desert surface behind the solid native dilution agent of SH, is used for fixing migrating dune simultaneously.Solidify dried sand dune and have good globality and weather-proof property.

Summary of the invention

Fixing the sand is to spray at surface layer of desert, forms one deck glued membrane and gets final product, and does not carry, do not have precipitation after the curing, does not therefore need too high compressive strength.And solidifying beach salty soil uses as embankment or building lot, then needs certain intensity and water stability.

The method that the purpose of this invention is to provide a kind of solidifying beach salty soil, adopt optimum curing materials to cooperate rolling method when, make the technical indicators such as compressive strength, California Bearing Ratio CBR, rebound deflection, the modulus of resilience of solidifying beach salty soil all can satisfy national standard " Code for design of building " (GB50007-2002) and the technical requirements of industry standard " highway subgrade design specifications " (JTG D30-2004), solidifying beach salty soil can be used as building lot and Expressway Embankment.

The object of the invention is achieved through the following technical solutions:

Solid native agent of admixture SH and quicklime in the dry ground of beach salty soil, the addition content of the solid native agent of SH is 4% of a dry ground quality, and the quicklime volume is 8% of a dry ground quality, and the quicklime grade can be secondary.Concrete curing schedule comprises:

1. in beach salty soil, sprinkle water equably with the sprinkling truck, the moisture content of soil is remained on less than 3-5 percentage points of optimum moisture contents;

2. quicklime is spread equably be layered on above, with turnplow upset, mix and stir 2 times, form the rendzinas compound;

The solid native agent of SH is soluble in water 3., make solution, the water yield sprays this solution on the rendzinas compound in step 2 then equably for solidifying 3%～5% of the dry ground quality handled;

4. overturn, mix and stir compound 2 times with turnplow again, make curing materials and moisture distribution even.With the road camber shape of compound leveling, use road roller static pressure 1 time, the vibration 2 times of 20T again to regulation.Static pressure 1 time more at last.

Advantage of the present invention and characteristics:

(1) solves the softening problem of single quicklime solidifying beach salty soil moisture absorption, improved the intensity and the water stability (comparison of compressive strength before and after the immersion) of solidified earth.

(2) the inventive method confirms that solidification effect is good through on-site rolling test with fill quality examination, satisfies technical requirements such as the compressive strength of filling Expressway Embankment, bearing ratio CBR, rebound deflection, the modulus of resilience.

The specific embodiment

In order to understand the present invention, further specify by embodiment, but do not limit the present invention.

Embodiment

With fork lift truck earth material being transported to test site spreads out.Soil is silty clay, index of plasticity 12.Road roller adopts XSM220 type vibratory roller, 20 tons of work qualities, vibration frequency 28HZ, exciting force 350/200kN.The filler construction technology adopts road-mix method.

The work progress of (1) the solid native agent of 4%SH+8% quicklime+salinized soil

With road-mixed machine the soil block of napping is forced to be crushed to particle diameter less than 10cm, with bulldozer filler is shakeout and is made into the road camber shape of regulation then, loose laying depth 0.3m.Spread shop 8% quicklime, overturn, mix and stir 2 times with turnplow.The solid native agent of SH with 4% is water-soluble, and the water yield of adding should make the moisture content of earth material reach optimum moisture content.With the sprinkling truck it is evenly spilt in soil, overturn, mix and stir 2 times with turnplow again.The leveling compound rolls with 20 tons of road rollers, first static pressure 1 time, vibroroller cmpacting 2 times, static pressure 1 time more at last again.

(2) rolling effect and solidification intensity test

For the rolling effect that detects solidified earth and mechanical property index with the increasing law of curing age, get test block by different curing age, carry out rolling effect (dry density), shear strength, compressive strength and modulus of compressibility test.Test result sees Table 1, table 2.

The dry density of table 1 field trial solidified earth and compressive strength test result

Table 2 field trial solidified earth shear strength and modulus of compressibility test result

Solidifying beach salty soil increases with curing age, and compressive strength is increasing gradually.Since the 3rd week, the compressive strength of solidifying beach salty soil increasess slowly, but water stability is greatly improved.

(3) the pavement performance index test of solidified earth

Test rolls the degree of compaction, road surface rebound deflection, the modulus of resilience, bearing ratio of embankment etc., whether satisfies the requirement of " highway subgrade design specifications " (JTG D30-2004) and checking engineering Application feasibility with the check rolling effect.The Expressway Embankment the key technical indexes sees Table 3.

The requirement of table 3 Expressway Embankment the key technical indexes

The 6th week carried out on-the-spot detection after solidifying beach salty soil on-site rolling test is finished, the result is as follows:

1) degree of compaction test

Degree of compaction adopts sand replacement method to test, three points of every section test.The degree of compaction that records 8% quicklime+beach salty soil is 95.4%; The degree of compaction of the solid native agent of 4%SH+8% quicklime+beach salty soil is 96.3%.Test confirms, with 20T road roller static pressure 2 times, the roller compaction construction method that vibroroller cmpacting is 2 times can satisfy 95% the compaction requirement of going up that embankment requires.

2) California Bearing Ratio CBR test

California Bearing Ratio CBR adopts the loaded plate method, and instruction carriage adopts the east wind of rear axle 10T to load wagon drill.The California Bearing Ratio CBR that records 8% quicklime+beach salty soil test section is 30%, and the California Bearing Ratio CBR of the solid native agent of 4%SH+8% quicklime+beach salty soil test section is 40%, satisfies far away and goes up roadbed greater than 8% requirement.

3) rebound deflection test

Rebound deflection adopts Beckman beam method, and instruction carriage adopts the east wind of rear axle 10T to load wagon drill.Record the average deflection value 32 of calculating (0.01mm) of the solid native agent of 4%SH+8% quicklime+beach salty soil test section, standard deviation 13 (0.01mm) is calculated and is represented deflection value 45 (0.01mm).Satisfying the top roadbed should be less than the deflection value requirement of 200～250 (0.01mm).

4) modulus of resilience test

The modulus of resilience adopts the loaded plate method.Instruction carriage adopts the east wind of rear axle 10T to load wagon drill.Record the soil matrix modulus of resilience E of 8% quicklime+beach salty soil test section ₀Be 239MPa; The solid native agent of 4%SH+8% quicklime+beach salty soil test section soil matrix modulus of resilience E ₀Be 499MPa.Satisfy roadbed top soil matrix modulus of resilience E ₀Should reach the quality requirement of 38.5MPa.

The on-the-spot testing result of test embankment confirms that after the inventive method was handled, its compressive strength, degree of compaction, California Bearing Ratio CBR, road surface rebound deflection, the modulus of resilience can both satisfy the quality requirement that embankment fills when beach salty soil used as embankment.

Claims

1, a kind of method of solidifying beach salty soil is characterized in that solid native agent of admixture SH and quicklime in the dry ground of beach salty soil, and the addition content of the solid native agent of SH is 4% of a dry ground quality, and the quicklime volume is 8% of a dry ground quality; Concrete curing schedule comprises:

1) in beach salty soil, sprinkles water equably with the sprinkling truck, the moisture content of soil is remained on less than 3-5 percentage points of optimum moisture contents;

2) quicklime is spread equably be layered on above, with turnplow upset, mix and stir 2 times, form the rendzinas compound;

3) the solid native agent of SH is soluble in water, make solution, the water yield sprays this solution in step 2 then equably for solidifying 3%～5% of the dry ground quality handled) in the rendzinas compound on;

4) overturn, mix and stir step 3) gained compound 2 times with turnplow again, make curing materials and moisture distribution in the step 3 gained compound even; With the road camber shape of step 3) gained compound leveling, use road roller static pressure 1 time, the vibration 2 times of 20T again to regulation; Static pressure 1 time more at last.