CN111236246A - Method for constructing waterproof curtain of foundation pit - Google Patents

Abstract

The invention relates to the technical field of foundation pit construction, in particular to a method for constructing a waterproof curtain of a foundation pit, which comprises the following steps of: s1, preparing construction; s2, measuring and positioning; s3, drilling; s4, preparing cement mortar; s5, performing rotary spraying grouting to form a rotary spraying pile; s6, repeating the steps to construct other jet grouting piles until all the jet grouting piles are completely constructed; the cement mortar comprises the following components in parts by weight: 100 parts of Portland cement; 60-70 parts of talcum powder; 60-70 parts of dolomite powder; 50-60 parts of zircon powder; 40-50 parts of fluorite powder; 3-5 parts of di-n-butyl tellurium; 0.5-0.6 part of indium nitride; 90-110 parts of water. The invention has the advantages of good water seepage prevention effect of the jet grouting pile, better underground water blocking effect of the waterproof curtain and better water stopping effect.

Description

Method for constructing waterproof curtain of foundation pit

Technical Field

The invention relates to the technical field of foundation pit construction, in particular to a method for constructing a waterproof curtain of a foundation pit.

Background

At present, in order to prevent or reduce the inflow of underground water into the foundation pit from the side wall and the bottom of the foundation pit, a waterproof curtain is usually arranged on the periphery of the foundation pit.

The existing waterproof curtain usually adopts the side-by-side jet grouting piles to surround the foundation pit so as to form a continuous waterproof curtain, construction of the jet grouting piles can be completed only by drilling and then spraying, construction is convenient, and surrounding geological structures are not easily influenced.

The above prior art solutions have the following drawbacks: the jet grouting pile is formed by pouring cement mortar, a large amount of capillary structures can be formed after the cement mortar is solidified, water seepage can still exist to a certain degree, the water stopping effect is general, and therefore the space is improved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for constructing a waterproof curtain of a foundation pit, which has a better waterproof effect.

The above object of the present invention is achieved by the following technical solutions:

a method for constructing a waterproof curtain of a foundation pit comprises the following steps:

s1, preparing construction;

s2, measuring and positioning;

s3, drilling;

s4, preparing cement mortar;

s5, performing rotary spraying grouting to form a rotary spraying pile;

s6, repeating the steps to construct other jet grouting piles until all the jet grouting piles are completely constructed;

the cement mortar comprises the following components in parts by weight:

100 parts of Portland cement;

60-70 parts of talcum powder;

60-70 parts of dolomite powder;

50-60 parts of zircon powder;

40-50 parts of fluorite powder;

3-5 parts of di-n-butyl tellurium;

0.5-0.6 part of indium nitride;

90-110 parts of water.

By adopting the technical scheme, the talcum powder, dolomite powder, zircon powder, fluorite powder and other powdery fillers are adopted in the cement mortar, so that gaps formed in the cement mortar are fewer, a capillary structure is reduced, the water seepage prevention effect of the jet grouting pile is better, the underground water blocking effect of the waterproof curtain is better, and the water stopping effect is better;

the talcum powder enables the cement mortar to have better fluidity, so that the cement mortar is easy to spray, is suitable for a rotary spraying process and is convenient to construct;

through the matching of dolomite powder, zircon powder and fluorite powder, the structural strength of the jet grouting pile is higher, so that the structural stability of the jet grouting pile is improved, the waterproof curtain also has a better effect of reinforcing the soil at the edge of the foundation pit while stopping water, the side wall of the foundation pit is more stable, and the pressure of foundation pit support is reduced;

through adding di-n-butyl tellurium, indium nitride in cement mortar for the impervious ability of jet grouting pile further improves, makes the effect that waterproof curtain stopped groundwater better, and the stagnant water effect is better.

The present invention in a preferred example may be further configured to: in the step S5, during the rotary spraying, the guniting device is inserted into the soil at the bottom of the hole, and the guniting device is lifted after the rotary guniting device is inserted for 30-60S.

By adopting the technical scheme, the guniting equipment is used for rotating guniting in soil at the bottom of the hole for 30-60 s, so that the pile end soil at the bottom of the hole and cement mortar are fully stirred to form a transition section, the connection stability of the bottom of the rotary guniting pile and the soil is improved, and the rotary guniting pile is more stable.

The present invention in a preferred example may be further configured to: in step S5, when the guniting device is lifted, the guniting device rotates in the reverse direction.

Through adopting above-mentioned technical scheme, be reverse rotation through the whitewashing for the whitewashing is more even, makes pile tip soil mix more evenly with cement thick liquid under reverse acting force simultaneously, has further improved the stability of spouting the stake soon.

The present invention in a preferred example may be further configured to: the cement mortar also comprises the following components in parts by mass:

4-6 parts of glass fiber.

Through adopting above-mentioned technical scheme, through adding glass fiber in cement mortar, effectively the reinforcement spouts the stake soon for spout a stable in structure soon, difficult fracture.

The present invention in a preferred example may be further configured to: the cement mortar also comprises the following components in parts by mass:

1-2 parts of a silane coupling agent.

Through adopting above-mentioned technical scheme, through adding silane coupling agent in cement mortar in order to cooperate glass fiber for glass fiber reinforcement spouts the effect of stake soon better, has further improved the structural stability who spouts the stake soon.

The present invention in a preferred example may be further configured to: the cement mortar also comprises the following components in parts by mass:

3-5 parts of granite powder;

3-5 parts of basalt powder.

Through adopting above-mentioned technical scheme, through adding granite mountain flour, basalt mountain flour in cement mortar, effectively improve the compressive strength of jet grouting pile for the structural stability of jet grouting pile is better, plays the effect of better auxiliary stay foundation ditch soil all around.

The present invention in a preferred example may be further configured to: the cement mortar also comprises the following components in parts by mass:

0.3-0.4 part of indium oxide.

By adopting the technical scheme, the anti-permeability performance of the jet grouting pile is further improved by adding the indium oxide, the di-n-butyl tellurium and the indium nitride into the cement mortar for matching, so that the water stopping effect of the water stopping curtain is further improved.

The present invention in a preferred example may be further configured to: the step S4 of preparing cement mortar specifically comprises the following steps:

s41, mixing portland cement and water, and uniformly stirring to form cement slurry;

s42, adding di-n-butyl tellurium and indium nitride into the cement slurry, and uniformly stirring to form a premix;

s43, adding talcum powder, dolomite powder, zircon powder and fluorite powder into the premix, and uniformly stirring to form cement mortar.

By adopting the technical scheme, the di-n-butyl tellurium and the indium nitride are uniformly dispersed in the cement slurry, so that the anti-permeability effect of the jet grouting pile formed by the prepared cement mortar is ensured, and the quality of the cement mortar is higher.

The present invention in a preferred example may be further configured to: and in the step S42, glass fiber, a silane coupling agent, granite stone powder, basalt stone powder and indium oxide are also added.

By adopting the technical scheme, after the prepared cement mortar is prepared into the jet grouting pile, the jet grouting pile has better compression resistance, cracking resistance, impermeability and quality.

In summary, the invention includes at least one of the following beneficial technical effects:

1. by adopting powdery fillers such as talcum powder, dolomite powder, zircon powder, fluorite powder and the like in the cement mortar, the gaps formed in the cement mortar are less, the capillary structure is reduced, the water seepage prevention effect of the jet grouting pile is better, the underground water blocking effect of the waterproof curtain is better, and the water stopping effect is better;

2. by adding di-n-butyl tellurium, indium nitride and indium oxide into cement mortar, the impermeability of the jet grouting pile is further improved, the effect of the waterproof curtain on blocking underground water is better, and the waterproof effect is better;

3. by adding granite powder and basalt powder into cement mortar, the compressive strength of the jet grouting pile is effectively improved, the structural stability of the jet grouting pile is better, and a better effect of assisting in supporting soil around a foundation pit is achieved.

Drawings

FIG. 1 is a schematic flow chart of a method for constructing a waterproof curtain of a foundation pit according to the invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

In the following examples and comparative examples:

the portland cement is anti-sulfate portland cement sold by the DongSheng building material Ministry in the Bay of Shawan in Leshan City;

the water reducing agent is an FDN high-efficiency water reducing agent sold by Zhengzhou Jinfengda chemical product limited company;

the talcum powder is 1250-mesh talcum powder sold by Jinnan Xinyi chemical industry Co., Ltd;

the dolomite powder is sold by Shengfei mineral product processing factories in Lingshou county;

the zircon powder is the zircon powder sold by Guangmeng mineral product processing factories in Lingshui county;

the fluorite powder is sold by Tianlong mineral product processing factories in Lingshu county;

the di-n-butyl tellurium is sold by Jinjinle industry Co Ltd of Shanghai;

the indium nitride is indium nitride sold by Shanghai Chengxao biological technology limited;

the glass fiber is alkali-free chopped glass fiber sold by Hebeijing aviation mineral products, Inc.;

the granite stone powder is 1250 mesh granite stone powder sold by Lingshou county john's jade product processing factories;

the basalt stone powder is sold by Lingshou county stone ore processing factories;

the indium oxide is available from Shanghai Boehn chemical technology Co., Ltd.

Example 1

Referring to fig. 1, the method for constructing the waterproof curtain of the foundation pit disclosed by the invention comprises the following steps:

s1, construction preparation, which comprises the following steps:

leveling the site, removing all barriers above and below the ground at the pile position, backfilling and tamping the low-lying position of the site with viscous soil, and making a slurry discharge ditch.

S2, measuring and positioning, specifically comprising the following steps:

firstly, a total station is adopted to discharge a control pile in a test area according to the pile number of a high-pressure jet grouting pile, then a steel tape and a hemp thread are used to transfer the pile position of the discharged jet grouting pile according to the pile distance, a small bamboo stick is used for marking, and a lime mark is scattered;

then the pile driver is moved to a construction position, a specially-assigned person commands the pile driver, a horizontal ruler and a positioning measuring hammer are used for calibrating the pile driver, the guide frame and the drill rod are made to be vertical to the ground, the inclination rate is less than 1.5%, the drill rod which does not meet the requirement of verticality is adjusted until the verticality of the drill rod meets the requirement, in order to ensure the accuracy of the pile position, a positioning card is used, and the centering error of the pile position is less than 5 cm.

S3, drilling, specifically comprising the following steps:

the drilling machine is started, drilling is carried out while rotating, the double-pipe rotary spraying method is adopted for construction, the pipe inserting operation is simultaneously completed when the drilling is completed, in the pipe inserting process, in order to prevent the sand from blocking the nozzles, the high-pressure water nozzles jet water while inserting the pipes, the water pressure is 0.8MPa, and the drilling is stopped after the water pressure reaches the designed elevation.

S4, preparing cement mortar, which comprises the following steps:

s41, adding 100kg of Portland cement, 110kg of water and 9kg of water reducing agent into a stirring kettle, stirring at the rotating speed of 60r/min for 3min to form cement slurry;

s42, adding 3kg of di-n-butyl tellurium and 0.5kg of indium nitride into the cement slurry at the rotating speed of 60r/min, and stirring for 2min to form a premix;

s43, adding 60kg of talcum powder, 60kg of dolomite powder, 50kg of zircon powder and 40kg of fluorite powder into the premix, stirring at the rotating speed of 45r/min for 8min to form cement mortar.

S5, performing rotary spraying grouting, which specifically comprises the following steps:

the high-pressure equipment and the piping system are checked before the insertion of the swozzle, and the pressure and the displacement of the equipment must meet the design requirements. Sealing rings at all parts are required to be good, sundries cannot be left in all channels and nozzles, a high-pressure water jet test is carried out, and cement mortar can be sprayed after the sealing rings are qualified;

various technological parameters of the rotary spraying operation system are controlled according to preset requirements, and records about rotary spraying time, slurry consumption, slurry emitting conditions, pressure changes and the like are made at any time;

during injection, inserting the rotary jet pipe into pile end soil at the bottom of a drill hole, after the injection pressure of the rotary jet pipe reaches 24MPa, spraying and rotating for 30 seconds, fully stirring cement mortar and the pile end soil, then, spraying and rotating at a constant speed in a reverse direction to lift the grouting pipe, wherein the lifting speed is 200mm/min, and when the distance between the lifting speed and the lifting speed is 1m from the pile top, the stirring speed and the lifting speed are reduced to ensure the pile top to be compact and uniform, when a fault occurs in the middle, the lifting and the rotary jet are stopped to prevent the pile body from being interrupted, meanwhile, the fault is immediately checked and eliminated, the lap joint of a hole section for spraying and grouting with the front section is restarted to be not less than 1m, and the disjoint;

after the injection construction is finished, the grouting pipes and other equipment are washed clean by clear water to prevent solidification and blockage, no cement slurry can remain in the pipes or in the machines, and the cement mortar is changed into the clear water to be injected on the ground so as to completely remove the slurry in the slurry pump, the grouting pipes and the hoses.

And S6, repeating the steps to construct other jet grouting piles until all the jet grouting piles are completely constructed.

Example 2

The difference from example 1 is that:

s4, preparing cement mortar, which comprises the following steps:

s41, adding 100kg of Portland cement, 100kg of water and 10kg of water reducing agent into a stirring kettle, stirring at the rotating speed of 60r/min for 3min to form cement slurry;

s42, adding 4kg of di-n-butyl tellurium and 0.55kg of indium nitride into the cement slurry at the rotating speed of 60r/min, and stirring for 2min to form a premix;

s43, adding 65kg of talcum powder, 65kg of dolomite powder, 55kg of zircon powder and 45kg of fluorite powder into the premix, stirring at the rotating speed of 45r/min for 8min to form cement mortar.

Example 3

The difference from example 1 is that:

s4, preparing cement mortar, which comprises the following steps:

s41, adding 100kg of Portland cement, 90kg of water and 11kg of water reducing agent into a stirring kettle, stirring at the rotating speed of 60r/min for 3min to form cement slurry;

s42, adding 5kg of di-n-butyl tellurium and 0.6kg of indium nitride into the cement slurry at the rotating speed of 60r/min, and stirring for 2min to form a premix;

s43, adding 70kg of talcum powder, 70kg of dolomite powder, 60kg of zircon powder and 50kg of fluorite powder into the premix, stirring at the rotating speed of 45r/min for 8min to form cement mortar.

Example 4

The difference from example 1 is that:

s4, preparing cement mortar, which comprises the following steps:

s41, adding 100kg of Portland cement, 100kg of water and 10kg of water reducing agent into a stirring kettle, stirring at the rotating speed of 60r/min for 3min to form cement slurry;

s42, adding 3.3kg of di-n-butyl tellurium and 0.5kg of indium nitride into the cement slurry, stirring for 2min at the rotating speed of 60r/min to form a premix;

s43, adding 66kg of talcum powder, 68kg of dolomite powder, 52kg of zircon powder and 47kg of fluorite powder into the premix, stirring at the rotating speed of 45r/min for 8min to form cement mortar.

Example 5

The difference from example 4 is that:

in step S42, 4kg of glass fiber was also added.

The glass fiber length was 2 mm.

Example 6

The difference from example 4 is that:

5kg of glass fiber was also added in step S42.

The glass fiber length was 2 mm.

Example 7

The difference from example 4 is that:

in step S42, 6kg of glass fiber was also added.

The glass fiber length was 2 mm.

Example 8

The difference from example 4 is that:

5.5kg of glass fiber was also added in step S42.

The glass fiber length was 2 mm.

Example 9

The difference from example 4 is that:

in step S42, 4kg of glass fiber and 1kg of silane coupling agent are also added.

The glass fiber length was 2 mm.

Example 10

The difference from example 4 is that:

in step S42, 5kg of glass fiber and 1.5kg of silane coupling agent are also added.

The glass fiber length was 2 mm.

Example 11

The difference from example 4 is that:

in step S42, 6kg of glass fiber and 2kg of silane coupling agent are also added.

The glass fiber length was 2 mm.

Example 12

The difference from example 4 is that:

in step S42, 5.5kg of glass fiber and 1.8kg of silane coupling agent are also added.

The glass fiber length was 2 mm.

Example 13

The difference from example 4 is that:

in step S42, 3kg of granite powder and 3kg of basalt powder are also added.

Example 14

The difference from example 4 is that:

in step S42, 4kg of granite powder and 4kg of basalt powder are also added.

Example 15

The difference from example 4 is that:

5kg of granite powder and 5kg of basalt powder are also added in the step S42.

Example 16

The difference from example 4 is that:

in step S42, 4.5kg of granite powder and 4.5kg of basalt powder are also added.

Example 17

The difference from example 4 is that:

0.3kg of indium oxide was also added in step S42.

Example 18

The difference from example 4 is that:

0.35kg of indium oxide was also added in step S42.

Example 19

The difference from example 4 is that:

0.4kg of indium oxide was also added in step S42.

Example 20

The difference from example 4 is that:

0.33kg of indium oxide was also added in step S42.

Example 21

The difference from example 4 is that:

in step S42, 4kg of glass fiber, 1kg of silane coupling agent, 3kg of granite stone powder, 3kg of basalt stone powder and 0.3kg of indium oxide are also added.

The glass fiber length was 2 mm.

Example 22

The difference from example 4 is that:

in step S42, 5kg of glass fiber, 1.5kg of silane coupling agent, 4kg of granite stone powder, 4kg of basalt stone powder and 0.35kg of indium oxide are also added.

The glass fiber length was 2 mm.

Example 23

The difference from example 4 is that:

6kg of glass fiber, 2kg of silane coupling agent, 5kg of granite stone powder, 5kg of basalt stone powder and 0.4kg of indium oxide are also added in the step S42.

The glass fiber length was 2 mm.

Example 24

The difference from example 4 is that:

in step S42, 5.5kg of glass fiber, 1.8kg of silane coupling agent, 4.5kg of granite stone powder, 4.5kg of basalt stone powder and 0.33kg of indium oxide are also added.

The glass fiber length was 2 mm.

Comparative example 1

The difference from example 4 is that:

no di-n-butyl tellurium was added to S42.

Comparative example 2

The difference from example 4 is that:

indium nitride was not added to S42.

Comparative example 3

The difference from example 4 is that:

no di-n-butyl tellurium or indium nitride was added to S42.

Experiment 1

The cracking index of the samples prepared by the cement mortar prepared in each example and each comparative example is detected according to GB/T29417-2012 test method for the drying shrinkage cracking performance of the cement mortar and concrete.

Experiment 2

The 7d compressive strength (MPa) and 28d compressive strength (MPa) of the samples prepared by the cement mortar prepared in the examples and the comparative examples are detected according to the compressive strength test in GB/T50081-2002 Standard test method for mechanical properties of ordinary concrete.

Experiment 3

The impermeability grade of the samples prepared by the cement mortar prepared in each example and comparative example is detected according to the water permeability resistance test in GB/T50082-2009 Standard test method for testing long-term performance and durability of ordinary concrete.

The specific experimental data are shown in Table 1

TABLE 1

According to the comparison of the data of comparative examples 1-3 and example 4 in table 1, the di-n-butyl tellurium and indium nitride are added into cement mortar independently, so that no obvious negative effect is caused on the physical properties of the sample prepared by the cement mortar, and when the di-n-butyl tellurium and the indium nitride are added simultaneously and are matched in proportion, the impermeability of the sample prepared by the cement mortar is effectively improved, so that the jet grouting pile has better impermeability, and the water stopping effect of the water stopping curtain is better.

According to the comparison of the data of the examples 5-8 and the example 4 in the table 1, the glass fiber is added into the cement mortar, so that the cracking resistance of the sample prepared by the cement mortar is effectively improved, the structure of the jet grouting pile is stable and is not easy to crack, the effect of assisting in supporting the foundation pit is better achieved, and the burden of a foundation pit supporting structure is reduced.

According to the comparison of the data of examples 9-12 and example 4 in table 1, the silane coupling agent is added to the cement mortar to match with the glass fiber, so that the effect of reinforcing the jet grouting pile is better, and the jet grouting pile is more stable.

According to comparison of data of examples 13-16 and example 4 in table 1, granite powder and basalt powder are added into cement mortar, so that the compressive strength of a sample prepared from the cement mortar is effectively improved, the structural stability of the jet grouting pile is further improved, a waterproof curtain better assists a foundation pit supporting structure, and a foundation pit is more stable.

According to the comparison of the data of the examples 17-20 and the example 4 in the table 1, the addition of the indium oxide in the cement slurry in combination with the di-n-butyl tellurium and the indium nitride further improves the impermeability of the sample prepared by the cement mortar, thereby further improving the impermeability of the jet grouting pile and enabling the water stopping effect of the water stopping curtain to be better.

According to the data of examples 21-24 in table 1, the prepared cement mortar can be used to prepare a jet grouting pile with better cracking resistance, compressive strength and anti-permeability, so that the waterproof effect of the waterproof curtain is better.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims (9)

1. A method for constructing a waterproof curtain of a foundation pit is characterized by comprising the following steps: the method comprises the following steps:

s1, preparing construction;

s2, measuring and positioning;

s3, drilling;

s4, preparing cement mortar;

s5, performing rotary spraying grouting to form a rotary spraying pile;

s6, repeating the steps to construct other jet grouting piles until all the jet grouting piles are completely constructed;

the cement mortar comprises the following components in parts by weight:

100 parts of Portland cement;

60-70 parts of talcum powder;

60-70 parts of dolomite powder;

50-60 parts of zircon powder;

40-50 parts of fluorite powder;

3-5 parts of di-n-butyl tellurium;

0.5-0.6 part of indium nitride;

90-110 parts of water.

2. The method for constructing a foundation pit waterproof curtain as claimed in claim 1, wherein: in the step S5, during the rotary spraying, the guniting device is inserted into the soil at the bottom of the hole, and the guniting device is lifted after the rotary guniting device is inserted for 30-60S.

3. The method for constructing a foundation pit waterproof curtain as claimed in claim 2, wherein: in step S5, when the guniting device is lifted, the guniting device rotates in the reverse direction.

4. The method for constructing a foundation pit waterproof curtain as claimed in claim 1, wherein: the cement mortar also comprises the following components in parts by mass:

4-6 parts of glass fiber.

5. The method for constructing a foundation pit waterproof curtain as claimed in claim 4, wherein: the cement mortar also comprises the following components in parts by mass:

1-2 parts of a silane coupling agent.

6. The method for constructing a foundation pit waterproof curtain as claimed in claim 1, wherein: the cement mortar also comprises the following components in parts by mass:

3-5 parts of granite powder;

3-5 parts of basalt powder.

7. The method for constructing a foundation pit waterproof curtain as claimed in claim 1, wherein: the cement mortar also comprises the following components in parts by mass:

0.3-0.4 part of indium oxide.

8. The method for constructing a foundation pit waterproof curtain as claimed in claim 1, wherein: the step S4 of preparing cement mortar specifically comprises the following steps:

s41, mixing portland cement and water, and uniformly stirring to form cement slurry;

s42, adding di-n-butyl tellurium and indium nitride into the cement slurry, and uniformly stirring to form a premix;

s43, adding talcum powder, dolomite powder, zircon powder and fluorite powder into the premix, and uniformly stirring to form cement mortar.

9. The method for constructing a foundation pit waterproof curtain as claimed in claim 8, wherein: and in the step S42, glass fiber, a silane coupling agent, granite stone powder, basalt stone powder and indium oxide are also added.

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