CN110747706A

CN110747706A - Construction method for replacing weak soil of foundation bearing layer

Info

Publication number: CN110747706A
Application number: CN201910947268.9A
Authority: CN
Inventors: 范伟
Original assignee: China Second Metallurgy Group Co Ltd
Current assignee: China Second Metallurgy Group Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-02-04

Abstract

The application provides a construction method for replacing weak soil of a foundation bearing layer, and belongs to the technical field of road engineering construction. The construction method comprises the following steps: step one, base layer treatment, namely excavating a foundation pit on a road surface and tamping the excavated foundation pit; paving broken stones on the tamped foundation pit surface, and tamping the broken stone cushion layer; and step three, pouring concrete, namely pouring the concrete on the tamped broken stone cushion layer to form a concrete pavement and maintaining the pavement. The application provides a construction method of replacement ground holding layer weak soil, through the concrete that permeates water not only avoided the inconvenience that ponding brought, has good effect to washing hand ground noise and regulation space temperature and humidity moreover. The water permeability of the foundation is guaranteed through the broken stone cushion layer which is always laid in the foundation pit, the frost heaving resistance of the pavement structure can be improved, the load can be diffused, and the deformation of the foundation is reduced.

Description

Construction method for replacing weak soil of foundation bearing layer

Technical Field

The invention belongs to the technical field of road engineering construction, and particularly relates to a construction method for replacing weak soil of a foundation bearing layer, which is used for improving the condition of a soil foundation, improving the frost heaving resistance of a pavement structure and reducing the deformation of the soil foundation.

Background

In the prior art, when the pavement road construction is carried out, the soil foundation is diversified, and when the soil foundation is poor in condition, the problems of frozen soil, low frost heaving resistance, even pavement sinking and the like can be caused, so that the pavement concrete is seriously damaged, and the trip safety of people is influenced.

Disclosure of Invention

In view of the above, the present invention provides a construction method for replacing weak soil of a foundation bearing layer, so as to solve or overcome at least one technical problem in the prior art.

The application provides a construction method for replacing weak soil of a foundation bearing layer, which comprises the following steps:

step one, base layer treatment, namely excavating a foundation pit on a road surface and tamping the excavated foundation pit;

paving broken stones on the tamped foundation pit surface, and tamping the broken stone cushion layer;

and step three, pouring concrete, namely pouring the concrete on the tamped broken stone cushion layer to form a concrete pavement and maintaining the pavement.

Preferably, the step one includes:

and (4) erecting the mold in a working area, and controlling the height, the verticality and the water return gradient of the template.

Preferably, in the step one,

firstly, removing sundries such as humus soil;

adopting machinery to excavate a foundation pit, reserving a soil layer with the thickness of 10-20 cm on the surface of the foundation pit for manual cleaning, and preventing the foundation pit from being excavated too deep;

and tamping the foundation pit surface by using a tamping machine, and enabling the soil layer density of the foundation pit surface to reach a preset numerical value.

Preferably, the first step further comprises:

and detecting the density of the soil layer on the foundation pit surface after tamping by adopting a cutting ring method.

Preferably, in the second step, the quality of the crushed stone is controlled, impurities are removed, and the size range of the crushed stone particles is controlled.

Preferably, in the second step, the thickness of the laid gravel is more than or equal to 5cm, and finally, a tamping machine is adopted to tamp the gravel cushion layer.

Preferably, in the third step, the step (c),

paying off the gravel cushion layer at fixed points, wherein a preset distance is formed between every two points;

arranging a baffle plate at the edge of the gravel cushion layer;

and finally, pouring concrete to a preset elevation.

Preferably, before the concrete is poured, water is sprinkled on the gravel cushion layer, or a layer of mortar is laid.

Preferably, the concrete is pervious concrete.

Preferably, the time for transporting and paving the pervious concrete is less than or equal to 15 minutes, and the pervious concrete is paved in a blocking and cabin-separating mode;

tamping the pervious concrete by adopting a flat vibrator;

and coating the transparent sealing agent on the pervious concrete after the pervious concrete is formed and dried.

The application has the following beneficial effects:

the application provides a construction method of replacement ground holding layer weak soil, through the concrete that permeates water not only avoided the inconvenience that ponding brought, has good effect to washing hand ground noise and regulation space temperature and humidity moreover. The water permeability of the foundation is guaranteed through the broken stone cushion layer which is always laid in the foundation pit, the frost heaving resistance of the pavement structure can be improved, the load can be diffused, and the deformation of the foundation is reduced.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 is a construction flow chart of a replacement foundation bearing layer weak soil provided according to an embodiment of the invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

As shown in fig. 1, the present invention provides a construction method for replacing weak soil of a foundation bearing layer, comprising:

and (5) erecting the mold, wherein the mold is erected in a required working area. Constructors firstly separate the vertical formwork and the regional vertical formwork according to design requirements, and control the height, the perpendicularity and the water-reflecting gradient of the formwork in the process of vertical formwork. The region that makes the needs excavation through founding the mould is more regular, also plays the guard action, struts the region that will excavate through the template.

Step one, base layer treatment, namely excavating foundation pits on a road surface, and tamping the excavated foundation pits to preset requirements; firstly, the humus is removed, and the hidden trouble of ground subsidence in the future is avoided. When mechanical excavation is adopted, reserving a soil layer with the thickness of 10 cm-20 cm on the surface of the foundation pit for manual cleaning, and preventing the excavation from being too deep; when the excavation is too deep, backfilling with soil or fine stones or the like cannot be performed. And (4) tamping the plain soil by using a tamping machine to achieve the compactness of ramming the plain soil according to the design requirement. And (5) testing the density of the soil layer on the surface of the foundation pit by adopting a cutting ring method. If the soil layer density of the foundation pit surface does not meet the design requirement, tamping should be carried out again until the design requirement is met.

The cutting ring method is to cut a soil sample by a cutting ring with known mass and volume, the mass of the cutting ring is subtracted after weighing to obtain the mass of the soil, and the volume of the cutting ring is the volume of the soil, so that the density of the soil can be obtained.

firstly, the quality of the crushed stone is controlled, impurities are removed, and the size range of the crushed stone particles is controlled. Organic matters such as weathered macadam or branches are prevented from being mixed in the water, and the quality of macadam particles is guaranteed. When backfilling is carried out, elevation control points are arranged in the site, and the control points are protected. The thickness of the virtual pavements is used at the beginning so as to achieve the thickness of the gravel cushion layer after the gravel is tamped.

And (3) the thickness of the broken stones which are virtually paved (before the broken stones are tamped by a tamping machine) is more than or equal to 5cm, and finally, the tamping machine is adopted to tamp the broken stone cushion layer. In actual working conditions, specific analysis is carried out according to differences of the width, the load and the application of the pavement, and the size and the paving thickness of the applied broken stones are finally determined.

Paying off the gravel cushion layer at fixed points, wherein the interval between every two points is 10 meters; arranging a baffle plate at the edge of the gravel cushion layer; and finally, pouring concrete to a preset elevation.

In this embodiment, before the concrete is poured, water is sprinkled on the gravel cushion layer, or a layer of mortar is laid. The gravel cushion layer is sprayed with water or paved with mortar, so that the gravel cushion layer and the concrete are better condensed together, and the condensing effect is better.

In this embodiment, the concrete used in the above description is pervious concrete. The pervious concrete has good water permeability, and plays a good role in the permeability of water on the ground and the ecological environment.

In this embodiment, the pervious concrete is a dry concrete material, which has a fast initial setting, so the transport time is generally controlled according to the climatic conditions. The time for transporting and paving the pervious concrete is less than or equal to 15 minutes, paving is carried out in a blocking and separating mode, and the loose paving coefficient is 1.1. The concrete is evenly spread on the gravel cushion layer, the flatness is found by a drawing ruler, and a certain flooding degree is controlled.

When concrete is poured, the thickness and the strength must be controlled, and the strength stone detection work of the concrete is performed according to the construction drawing, so that the design standard can be met.

Tamping the pervious concrete by adopting a flat vibrator; after the paving is finished, the elevation and the flatness are inspected to meet the requirements. When the temperature is high, the concrete pavement is required to be immediately covered with a plastic film to keep the moisture in order to reduce the evaporation of the moisture. The water spraying can also be adopted for curing, and all the curing periods are not less than 7 days, so that the strength of the product is gradually improved in the curing period. The curing time is determined according to the construction temperature, the curing period is generally 14-21 days, the curing period is not less than 14 days at high temperature, the curing period is not less than 21 days at low temperature, the construction is carried out at the temperature of below 5 ℃, and the curing period is not less than 28 days.

And coating the transparent sealing agent on the pervious concrete after the pervious concrete is formed and dried. The transparent sealing agent can enhance durability and aesthetic property, and prevent the holes of the pervious concrete from being polluted and blocked due to overlong time.

The application provides a construction method of replacement foundation bearing stratum weak soil, through the concrete that permeates water not only avoided the inconvenience that ponding brought, has good effect to washing hand ground noise and regulation space temperature and humidity moreover. The water permeability of the foundation is guaranteed through the broken stone cushion layer which is always laid in the foundation pit, the frost heaving resistance of the pavement structure can be improved, the load can be diffused, and the deformation of the foundation is reduced. It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Finally, it should be noted that: it should be understood that the above examples are only for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims

1. A construction method for replacing weak soil of a foundation bearing layer is characterized by comprising the following steps:

2. The method for constructing a replacement foundation support layer weak soil according to claim 1, wherein the step one step further comprises:

3. The method for constructing a replacement foundation support layer weak soil according to claim 1, wherein in the first step,

firstly, removing sundries such as humus soil;

4. The method for constructing a replacement foundation support layer weak soil according to claim 3, wherein the first step further comprises:

5. The method as claimed in claim 1, wherein in the second step, the quality of the crushed stone is controlled, impurities are removed, and the size range of the crushed stone particles is controlled.

6. The construction method for replacing the weak soil of the foundation bearing stratum according to claim 1, wherein in the second step, the thickness of the laid broken stones is greater than or equal to 5cm, and finally, a tamping machine is adopted to tamp the broken stone cushion layer.

7. The method for constructing a replacement foundation support layer weak soil according to claim 1, wherein in the third step,

arranging a baffle plate at the edge of the gravel cushion layer;

and finally, pouring concrete to a preset elevation.

8. The method of claim 7, wherein water is sprayed on the gravel cushion layer or a mortar layer is laid before the concrete is poured.

9. The method for constructing a weak soil of replacement foundation support layer according to any one of claims 1 to 8, wherein the concrete is pervious concrete.

10. The method of constructing a replacement foundation support layer weak soil according to claim 9,

the time for transporting and paving the pervious concrete is less than or equal to 15 minutes, and the pervious concrete is paved in a blocking and compartment separation mode;

tamping the pervious concrete by adopting a flat vibrator;