CN108444892A - A kind of impervious sample production method of the soil cement of simplicity - Google Patents

Abstract

The invention discloses a simple method for preparing a cement-soil anti-seepage sample, which belongs to the technical field of geotechnical tests. The manufacturing device used mainly includes a sample preparation cylinder, a sample pressure plug, and a working backing plate with bolts. The sample preparation cylinder is a half cylinder, and the connecting bolts pass through the side flanges of the two opposite cylinder pieces. The lower end of the sample preparation cylinder has a flange, which is fixed to the working pad by bolts. The pressure sample plug squeezes the uniformly stirred cement soil to produce a cement soil sample, and then seals to obtain the sample required for the impermeability test. The samples obtained by the production method have a uniform degree of compaction, which can avoid cracks in the later curing process, and the method is simple and efficient to operate.

Description

A Simple Method for Making Cement-soil Impermeability Sample

technical field

The invention relates to a simple method for preparing a cement-soil anti-seepage sample, which belongs to the technical field of soil engineering.

Background technique

During the excavation of the foundation pit, there is generally a difference in water level inside and outside the foundation pit. Under the effect of water level difference, the water outside the foundation pit will seep into the foundation pit, and in severe cases, quicksand or surge will occur, causing damage to the foundation pit. The water-stop curtain can effectively prevent such damage, and the groundwater infiltrated in the foundation pit will be greatly reduced and can be discharged more easily. In the foundation pit excavation project, when the buried depth of the groundwater is relatively shallow and the permeability coefficient of the soil layer is relatively large, cement soil can be used as a material to set up a water-stop curtain around the foundation pit. Cement soil is a mixture of soil and cement. In engineering, high-pressure rotary grouting pile construction machinery is generally used to mix cement slurry into the soil body to form. Therefore, it is necessary to understand the anti-seepage characteristics of cement-soil in order to determine the optimal mixing ratio of cement in cement-soil, which requires the anti-seepage test of cement-soil.

The preparation of cement-soil impermeability samples is a very critical link, and the quality of the samples directly affects the accuracy of the test results. At present, there are two shapes of impermeability samples produced in the laboratory: cylindrical and frusto-conical. Considering that the cement-soil samples sampled by on-site core drilling are cylindrical, in order to facilitate the comparison with the test results of samples obtained on-site, the impermeability samples of cement-soil produced indoors should preferably be cylindrical. In the past, ring cutters were generally used to make such cylindrical samples.

In the process of making cylindrical samples with ring cutters, the cement soil is layered and compacted, which is likely to cause uneven compaction of the samples, and cracks are prone to appear at the joints between layers in the subsequent curing. These factors will have an impact on the test results, and it is urgent to develop a more reasonable cement-soil impermeability sample production device and formulate corresponding production methods.

Contents of the invention

The purpose of the present invention is to solve the deficiencies and problems existing in the prior art, and to provide a simple method for preparing a cement-soil anti-seepage sample.

The invention provides a simple method for making a cement-soil anti-seepage sample. The manufacturing device mainly includes a sample preparation cylinder, a sample pressure plug, and a working backing plate with bolts; the sample preparation cylinder is a half-type cylinder, and the connecting bolts Pass through the side flanges of two opposite cylinders; there is a bottom flange at the lower end of the cylinder, and there is a bolt hole in the middle of the bottom flange; an upward bolt is welded on the working backing plate, and the bolt passes through the bottom flange of the cylinder Bolt holes and corresponding nuts are installed to fix the sample preparation cylinder. The preparation method of the cement-soil anti-seepage sample mainly comprises the following steps:

Step 1: Take two cylinder pieces, put them together relatively, and connect them with bolts to form a sample preparation cylinder;

Step 2: Place the sample preparation cylinder on a flat work pad, adjust the position so that the bottom flange bolts pass through the corresponding bottom flange bolt holes, install and tighten the bottom flange nuts, and fix the sample preparation cylinder on the work pad board;

Step 3: Brush mineral oil on the inner wall of the sample preparation cylinder as a release agent, weigh the cement soil sample that has been stirred evenly, slowly pour it into the sample preparation cylinder, and level it;

Step 4: Take the pressure sample plug, put it into the sample preparation cylinder smoothly, and slowly apply pressure to make the upper surface of the pressure sample plug flush with the upper end surface of the sample preparation cylinder, and keep it under pressure for 5 minutes ;

Step 5: Loosen the side flange nuts and remove the side flange bolts, loosen and remove the bottom flange nuts, lift the sample preparation cylinder, separate the cylinder pieces, remove the pressure sample plug, and obtain the cement soil sample;

Step 6: Take a ring knife, place it flat on the hard plastic backing plate, put the cement soil sample obtained in step 5 into the middle position of the ring knife, make the gap between the cement soil sample and the inner wall of the ring knife uniform, and use a needle tube Inject heated paraffin liquid into the gap to ensure sealing, and after 1 hour, the cement-soil impermeability sample is obtained.

The sample preparation cylinder adopts a half type, which is to facilitate the removal of the prepared sample and avoid damage and damage to the sample when it is directly pushed out of the cylinder (such as a ring knife). The cement soil required to make a sample is loaded into the sample preparation cylinder at one time, which can avoid problems such as uneven compaction caused by layered compaction and subsequent cracks in the sample. Upward bolts are welded on the working backing plate for fixing the sample preparation cylinder.

The inner diameter of the sample preparation cylinder is 56mm, the outer diameter is 66mm, and the height is 80mm. This is because, when the impermeability test is carried out later, the sample needs to be put into the ring knife and sealed with wax. The ring knife has an inner diameter of 61.8mm and a height of 40mm. After the prepared sample is put into the ring knife, there is a gap of nearly 3.0 mm to meet the flow of the heated paraffin liquid, ensuring that the sample is tightly wrapped.

The diameter of the pressure sample plug is 55.4mm, and the height is 40mm. The height of the sample is 40mm, the height of the pressure sample plug is 40mm, and the height of the sample preparation cylinder is 80mm. When preparing samples, pour the weighed sample soil into the sample preparation cylinder. After leveling, put the sample plug into it, and squeeze the sample plug so that the upper surface of the sample plug is even with the top surface of the sample preparation cylinder. Qi, so a cement-soil sample with a diameter of 56mm and a height of 40mm was obtained.

The thickness of the side flange is equal to that of the bottom flange, and is twice the thickness of the tube wall. The thickness of the flange is thickened, which can restrain the deformation of the tube and facilitate the bolt connection.

The material of the sample preparation cylinder, the pressure sample plug, the working backing plate with bolts, and all the bolts and nuts are stainless steel. This is to ensure that the obtained sample is not polluted by rust, and also to increase the service life of the device.

Compared with the existing production method, the production method provided by the present invention can make the sample form at one time, avoiding the later cracking of the sample caused by multi-layer compaction; the sample is evenly stressed in the process of compacting cement soil , to ensure uniform compactness; the manufacturing device in this method is easy to manufacture and low in cost, and the sample manufacturing process of this method is simple, efficient and fast.

Description of drawings

Fig. 1 Schematic diagram of the structure of the present invention.

Figure 2 Schematic diagram of the front of the tube.

Figure 3 A-A sectional view of the tube.

Figure 4 Schematic diagram of the back of the tube.

Figure 5. Schematic side view of two cartridge assemblies.

Fig. 6 B-B sectional view of two tube assemblies.

Marked in the figure: 1-tube piece; 2-side flange bolt hole; 3-pressure sample plug; 4-side flange bolt; 5-sample soil; 6-side flange nut; 7-side flange; 8- Bottom flange; 9-working backing plate; 10-bottom flange bolt hole; 11-bottom flange bolt; 12-bottom flange nut.

Detailed ways

The following are specific embodiments of the present invention, and the technical solutions of the present invention are described in conjunction with the accompanying drawings.

Example

The simple method for making the cement-soil anti-seepage sample in this embodiment mainly includes a sample preparation cylinder, a sample pressure plug 3, and a working backing plate 9, as shown in Figs. 1 to 6 for details. Upward bottom flange bolts 11 are welded on the working backing plate 9, the bolts pass through the bottom flange bolt holes 10 on the bottom flange 8 of the cylinder piece 1, and corresponding bottom flange nuts 12 are installed to fix the sample cylinder. The bottom flange bolt 11 and the corresponding bottom flange nut 12 are called a bottom flange bolt assembly. The sample preparation cylinder is composed of two cylinder pieces 1, the bottom flange 8 is arranged at the lower end of the cylinder piece 1, and the side flange 7 is arranged on the side, and the side flange bolt holes 2 are arranged on the side flange 7. The side flange bolts 4 pass through the side flange bolt holes 2, and the side flange nuts 6 are tightened to assemble the two opposite cylinder pieces 1 into a sample preparation cylinder. The side flange bolt 4 and the corresponding side flange nut 6 are called a side flange bolt assembly. The thickness of the side flange 7 and the bottom flange 8 is 10 mm. The inner diameter of the sample preparation cylinder is 56mm, the outer diameter is 66mm, and the height is 80mm. The diameter of the sample plug 3 is 55.4mm, and the height is 40mm. The material of the sample preparation cylinder, the pressure sample plug 3, the bottom flange bolt assembly, the side flange bolt assembly, and the working backing plate 9 are all stainless steel. When making cement-soil impermeability samples, the following steps are adopted:

Step 1: Take two tube pieces 1, put them together relatively, take the side flange bolt 4 and the side flange nut 6, make the side flange bolt 4 pass through the side flange bolt hole 2, tighten the side flange nut 6, Form a sample cylinder;

Step 2: Place the sample preparation cylinder on the flat working backing plate 9, adjust the position so that the bottom flange bolts 11 pass through the corresponding bottom flange bolt holes 10, install and tighten the bottom flange nuts 12;

Step 3: Apply mineral oil to the inner wall of the sample preparation cylinder as a release agent, weigh the cement soil sample 5 that has been stirred evenly, slowly pour it into the sample preparation cylinder, and level it;

Step 4: Take the pressure sample plug 3 again, put it into the sample preparation cylinder smoothly, and apply pressure slowly so that the upper surface of the pressure sample plug 3 is flush with the upper end surface of the sample preparation cylinder, and under the pressurized state, Hold for 5 minutes, this is to avoid large rebound deformation of the formed cement-soil sample;

Step 5: Loosen and remove the side flange nut 6 and the bottom flange nut 12, lift the sample preparation cylinder, separate the cylinder piece 1, remove the pressure sample plug 3, and obtain the cement soil sample;

Step 6: Take a ring knife, place it flat on the hard plastic backing plate, put the cement soil sample obtained in step 5 into the middle position of the ring knife, make the gap between the cement soil sample and the inner wall of the ring knife uniform, and use a needle tube Inject heated paraffin liquid into the gap to ensure sealing, and after 1 hour, the cement-soil impermeability sample is obtained.

The above descriptions of the specific embodiments are only used to illustrate the present invention, and are not used to limit the protection scope of the present invention.

Claims (5)

1. A simple method for making a cement-soil impervious sample, characterized in that: the sample preparation device used mainly includes a sample preparation cylinder, a sample pressure plug, and a working backing plate with bolts; the sample preparation cylinder is a half cylinder , the connecting bolts pass through the side flanges of two opposite cylinders; the lower end of the cylinder has a bottom flange, and there is a bolt hole in the middle of the bottom flange; an upward bolt is welded on the working backing plate, and the bolt passes through the bottom of the cylinder Bolt holes on the flange and corresponding nuts are installed to fix the sample preparation cylinder; the preparation of the cement-soil impermeability sample mainly includes the following steps: Step 1: Take two cylinder pieces, put them together relatively, and connect them with bolts to form a sample preparation cylinder; Step 2: Place the sample preparation cylinder on a flat work pad, adjust the position so that the bottom flange bolts pass through the corresponding bottom flange bolt holes, install and tighten the bottom flange nuts, and fix the sample preparation cylinder on the work pad board; Step 3: Brush mineral oil on the inner wall of the sample preparation cylinder as a release agent, weigh the cement soil sample that has been stirred evenly, slowly pour it into the sample preparation cylinder, and level it; Step 4: Take the pressure sample plug, put it into the sample preparation cylinder smoothly, and slowly apply pressure to make the upper surface of the pressure sample plug flush with the upper end surface of the sample preparation cylinder, and keep it under pressure for 5 minutes ; Step 5: Loosen the side flange nuts and remove the side flange bolts, loosen and remove the bottom flange nuts, lift the sample preparation cylinder, separate the cylinder pieces, remove the pressure sample plug, and obtain the cement soil sample; Step 6: Take a ring knife, place it flat on the hard plastic backing plate, put the cement soil sample obtained in step 5 into the middle position of the ring knife, make the gap between the cement soil sample and the inner wall of the ring knife uniform, and use a needle tube Inject heated paraffin liquid into the gap to ensure sealing, and after 1 hour, the cement-soil impermeability sample is obtained. 2. The method for making a cement-soil impervious sample according to claim 1, characterized in that: the inner diameter of the sample preparation cylinder is 56 mm, the outer diameter is 66 mm, and the height is 80 mm. 3. The method for making the cement-soil anti-seepage sample according to claim 1, characterized in that: the diameter of the pressure sample plug is 55.4 mm, and the height is 40 mm. 4. The method for making the cement-soil anti-seepage sample according to claim 1, characterized in that: the thickness of the side flange and the bottom flange are equal, and twice the thickness of the tube wall. 5. The cement-soil anti-seepage sample preparation method according to claim 1, characterized in that: the material of the sample preparation cylinder, the pressure sample plug, the working backing plate with bolts, and all bolts and nuts is stainless steel.