Why should drill geological before construction

In addition to following the process, in order to meet the requirements, it is not easy at all, the work of calculating the stability of the items as well as the methods of construction. Much depends on the geological survey material. If the information is not complete or accurate information will lead to wrong design, lack of certainty, reduced safety of work. Can lead to many other dangerous consequences.

In the construction of the site, as well as our point of view, the geological survey is the basis for the design unit to propose solutions to design the foundation of some business buildings. but still ensure the technical requirements.

The concept of geological survey

Before exploring more about geological drilling as well as the importance of this stage, we need to understand this process. In our opinion, this is an important task to assess the conditional area. Perform by determining the hydrological conditions, mechanical properties of the soil layer, soil structure. For the purpose of designing the foundation, foundation. Major activities of this type are excavation, drilling, static, dynamic, static throw, horizontal compression.

When to conduct geological survey

Geotechnical drilling service Phan Tran said that according to the regulations of the Ministry of Construction, the construction works to be surveyed and the implementation process is specified in accordance with the law on state construction. Basically, construction works on weak soil and locations with complex conditions will have to do survey small or large drilling. In addition, the building has an area of ​​more than 250m2, buildings (from 3 floors up), important projects such as schools, hospitals, commercial centers, bridges and dams. This step is indispensable.

Reason for geological survey

Assess the safety of existing works, upgrades, renovations, designs, existing works as well as investigate the damage caused to the works.

Recognize changes in the future, and changes caused by the development, human impact, economic activity of the area are built... find solutions to problems or improve. It will happen in the build process and then.

Design, solution to build a reasonable platform and budget.

Whether the evaluation is appropriate for the work to be built or not.

Here we present the importance of geological drilling to survey. We hope you do not miss this step.

Experienced in soil treatment for ponds in Vietnam

Vietnam is an area where canals and ponds are very intricate, as the development of society, economics, science and population increases but the land area does not increase. To solve this problem, people fill ponds and ponds to build houses. The problem is that this will be a weak ground that needs to be treated before construction. Today, we introduce the method of pile foundation treatment.

One of the safeguards to build a foundation on a weak foundation is to use a foundation for housing. Pile foundation is becoming more and more popular, the number one choice is supposed to be when encountering this geological form.

Pile foundation is a type of nail that is placed above the pile to form pile groups linking the braces and the foundation to create a solid foundation. The basement is used in situations where there are complex terrain, weak soil such as ponds, lakes, plain land, weak areas.

Select the number of piles

Typically, when the design of the home does not include geological survey reports, it is extremely important to accurately calculate the number of piles to avoid wastage, which is directly related to the economic problems of the owner. .

The number of piles for each station depends on the load being transmitted to the top of the column, the depth of the foundation being buried, but the depth of burial is not related too much to determine the number of piles. To calculate the number of piles can be as follows:

Load floor, wall load, dynamic load due to total usage 1.2-1.5 tons / m2 x load capacity of column coefficient x 1.2x the number of floors.

For example: calculate the number of piles 200x200 with the capacity of 20t / pile head, for the column with the load area of ​​20m2 (5 * 4) => the number of piles = 1.2 * 20 * 1,2 * 1 = 28, 8 tons / 20 = 1.44 piles => select 3 piles in this case to ensure the nails work simultaneously in two directions.

Size

For 4 piles we use 1000 x 1000 x 700 and put steel ф12a150. The steel stake is associated with steel plates and steel beams forming a block.

Grout size 300 x 600, put steel on 3ф20, lower and ф8a150 for steel belt.

Note: However, for grade 4 houses, the use of pile foundation is relatively low due to high pile costs as well as unnecessary foundation.

Selection of pile presses

The load of the pile 200x200 = 20t is the pile head bearing static load 20t, the load on the pile is the dynamic load during construction, the dynamic load is usually 2-3 times static load, it is also loaded on the top of the pile. Therefore, the compression load at the pile head 200 * 200 is 20 * 2-20 * 3t = 40-60t.

When choosing the pile for base treatment, the force must be greater than 15% of the dynamic load => pile presses must be> = 75t.

When stacked, there will be a switchboard from the clock to the actual pressure, just watch the meter at your watch that is capable of monitoring your work.

That is the note when using pile foundation in soil treatment that we summarize for you readers. Hopefully the article can help you understand better to be able to understand and know what your unit is doing, is standard. Thank you for following the article.

The conditions that cause the soil to sink

Geological survey is an indispensable work in the process of preparing the construction. Survey results will determine whether the works are constructed or not, or how to decide on the foundation treatment process, what method, after having a stable background plan, the new works Execution. And the causes can cause subsidence status in the works. Let's go through it and learn some more things to know for you.

The problem of subsidence is uneven

Consequences of errors during land survey and in management of geological environment or significant economic losses. In order to minimize and remedy (sometimes irreparable), it is necessary to have a law on the protection and exploitation of the geological environment. The contents of these rules can not be expressed in the context of this article.

In the following, there are several unevenly solved situations that require attention in geological exploration to detect it before design and in finding the cause of failure when searching for remedies.

Ground conditions may cause uneven subsidence

The soil is compacted or sloping. This situation is often encountered in the construction of lowland valleys or river encroachment areas, industrial parks with ground leveling technology for use as natural compressive substrates, compaction, consolidation, such as pre-consolidation by sand piles, sand wells, and drainage. For large loads, use piles through the embankment, pay attention to slide along the slope, or slip the whole foundation as well as the works, protect the ground by collecting the surface drainage at the same time, to avoid permeability. flooded

The uneven distribution of tightness (when the ground is embankment) or there are rocks, building rubbish. Improved by static drilling or dynamic loading, sometimes using pile drilling...

The soil layer is uneven at the bottom of the foundation. The issue of unevenness is obvious if the structure is large. To avoid the need to combine the rational organization of the above structure (divided into independent units, increase hardness...), with the underlying foundation, the direction of land improvement (soil replacement, consolidation Use a soft pile like cement pile...) to treat the ground or use a foundation if the thickness of the soil changes drastically.

Having weak ground lenses under the nail: depending on the work on the strength of the structure or choose the appropriate solution including the use of piles through the lens, attention should be paid to the impact of sound on the pile.

Have weak soil at the beginning of the project: if it is thin, then dredge and replace with other good soil; If thick, use different solutions such as slits to cut work into monolithic blocks, or use piles through weak soil layers and resist the fine soil for both sections of the building.

The above are common problems when building foundation works, foundation treatment or geological survey. This is the case where it is necessary to improve the subsoil so that it does not collapse.

Plan for reinforcement of sandy soil

Sandstains are used when the soil is saturated with water, such as clay, saturated sand, peat with a very low surface thickness (less than 3m). That is the process of treating the ground to be applied, applied when our land belongs to the case as above.

The effect of mattress sand

Sandy Night is a kind of foundation treatment that is made from a thick layer of sand in the foundation of the water to be treated. They offer the following effects:

- Accelerates the consolidation speed of the platform, thereby increasing the load capacity of the floor and reducing the resolution process.

- Reduce the depth of the buried nails, thereby reducing the amount of construction material needed for the foundation.

- Reduced foundation settlement; Ground subsidence due to stress distribution by external load causes inside of soil under the sand layer.

- The sand layer acts as a load bearing layer, absorbing the load of the works into the natural soil layer, increasing the load capacity of the soil.

- However, in sand-cushioning, attention should be paid to the flow of sand, soil erosion by groundwater or liquefaction due to dynamic loads.

Should not use sand mattress

The size of the mattress is determined by calculating to meet two conditions: stability and durability of the building after the mattress is within the limits. The water table is high and pressure is high. At this point, it would be very costly to lower the water level and the cushion would be unstable and expensive. The substrate must be replaced with a thickness of over 3m, then the thick mattress will be thick and difficult to apply again without economic benefits.

Select unit for foundation treatment sand cushion

Weak soil and weak soil sand remediation is one of the most common construction works. So far in our country, the construction of this structure on weak land is not easy for the builder, poses many complex issues that need to be seriously studied, ensure stability and allow for solving. construction.

Construction methods of sand piles in the treatment of the foundation of the house

Sand pits are a part of the structural foundation of the house responsible for receiving and transmitting the load to the ground. Weak ground will be reinforced by a network of sand piles known as sand piles. This type of platform will bring some benefits and have certain construction methods. Together we learn about the construction characteristics of this type.

Sand pits function as a sand well that causes water in the soil to escape quickly through the sand hole. The consolidation and growth process will be accelerated and accelerated due to land treatment. The steel is plugged into the ground to make the platform tight. The soil is further compressed by the process of making holes. The water in the soil will be compressed into the hole drilled sand.

As a result, the ground is made of high strength after the treatment. It is also very simple to perform the ground treatment with this type of pile. Leaf material is quite inexpensive so the cost is also more economical to use other materials. Weak ground of 3 meters in length should use this type of pile to treat the foundation.

Effect of sand piles

Construction of this type is simple and relatively cheap material from gravel or rough sand, so the cost is relatively lower than cushion sand, the type of concrete foundation, the type used to treat other soil. This product is used to reinforce the weak soil more than 3 meters.

The width of the soil is reduced due to the compacted soil, so that the strength of the pile is improved. Helping pairs of pairs helps the voids in the soil escape faster for faster consolidation of the soil, the settling is reduced and more stable.

Note when installing sand piles

There is a note that it is not advisable to use sand piles in soils that are too dense (at the compression factor). Sand piles are not capable of compacting and are not suitable for weak soils that are less than 2m thick. For compacted sand piles, the soil must be reclaimed with high tensile strength by vibration energy to compact the sand in boreholes with a diameter of 60 to 80 cm.

With regular piles, this is a typical upstream vertical discharge for consolidation after 40cm borehole. Mineral is a major component and has high conductivity that can replace sand. Use compressed equipment and then put steel pipes in the soil then pour sand into.

Generally, sand piles are used to reinforce weak earths over 3m thick. Its advantages are also relatively high and the construction problem is not too complicated. However, if the construction contractor does not have the equipment, it can not be constructed or handled.

Guide to choosing quality concrete piles

One of the steps of the foundation is to prepare a reinforced concrete reinforced concrete column to plug into the foundation, reinforcing the soil for a more stable, to help the building does not collapse later. Phan Tran has assessed the quality of concrete piles to help the owner have a clear view and thoroughly understand the foundation treatment unit.

Pile shaft

Because the reinforcement is covered by a layer of concrete, it is impossible for us to check the material of the inner structure itself. However, it is still possible to proactively ask suppliers the following parameters to determine if it is a quality item.

Diameter and number of bars: the diameter of the pile should not be less than 14 mm, the pile diameter or the width is greater than 350 mm, the number of bars must not be less than 8.

Steel density: first determine the method of piling which we will use if the hammer contribution, the density of steel should not be less than 0.8%, the pile should not be less than 0.5% The shaft should not be smaller than 0.8%. Ask the contractor for a specification of the steel density and ask them to show you the type of concrete you intend to buy. In addition, if the landform terrain is white or has a thick layout, then choose the type of high density steel from 1 to 2%.

Concrete pile

It is difficult to identify the reinforcement so we need to get more information from the supplier, the pile manufacturer. However, we can still check the quality of the pile by the criteria such as the length, cross section of the concrete pile. Ensure that the concrete pile strength is not less than C30 and the thickness of the steel bar guard is less than 30 mm. If so, this can be considered a quality pile.

Pile connections

Concrete piles should be considered for pile connections and must meet the following requirements.

- When the design load is large, the small and long piles must penetrate the hard soil layer of a certain thickness. If it is in the earthquake or where many piles are concentrated, the welding method should be used.

- Joints must be secure and if they are seam joints, the pile should be easily identified.

- The number of joints must not exceed 2. In the shallow floor there is very difficult soil to penetrate over 3m thick, then the connector should be located at the bottom of the soil layer.

These are the criteria for selecting concrete piles to suit the specific soil treatment. We hope the article has brought useful information to readers, help you read closely track the background processing services for you.

Soil softening method when piling concrete

Foundation treatment is the critical process that determines the success of a project, affecting both life expectancy, sustainability in time, the prestige of the survey unit, the construction unit. Learn about methods of concrete pile press.

Hydraulic method

This is a large group of methods such as using piles, absorbent mesh, composite material, absorbent wick, vacuum pump, electrode.

Biological method

A new way to use microbial activity to change the characteristics of weak soil, reduce flooding in the geological works. This is a method of little interest, due to the relatively long construction period, but quite a bit of economic support.

Chemical methods

It is one of the focus groups in the past 40 years. Use chemicals to strengthen linkages in the soil such as cement, glass, silicate method ... Or some special chemicals for electrochemical purposes. Cement and cement piles are relatively convenient and popular. In less than 20 years, there have been active studies on strengthening reinforcement for cement piles. Glass use is less common because the power of this method is not very good, and the electrolyte is very low due to the relative technology required.

Thermodynamics

Is a unique method that can be used in combination with other ways in the natural environment. Use hot air over 8000 to change the physical properties of weak soil. This method is mainly used for geological conditions of clay or fine sandy soil. It requires a small amount of energy, but the results are fast and relatively positive.

Physical method

Including methods to lower the water level, using sand well, penetration wick, electric permeability.

Use dynamic load

Relatively common with geological conditions of sand or gravel such as vibrating roller, roller compactor. Piles, bamboo piles, cave piles, wooden piles are often applied for civil works. The use of mechanical foundation systems is mainly used to reinforce the soil in new buildings such as railways and roads. However, the use of explosives is highly effective in the short term, but is not suitable for clay and requires the professionalism of the builder.

Mechanical methods

It is one of the most commonly used foundation treatments, including static load balancing (pre-compression), dynamic load (vibration damping), waterproof piles, mechanical nails and deep explosives. sand piles, piles (sand piles, cement piles, lime piles), geotextile, cushions. Enhanced by mechanical agents.

Alternative methods

This is the usual way to overcome obstacles caused by weak soil, builders replace part or all of the weak soil in the new earthen force bearing high mechanical strength such as sand pillows, sand mattresses and time. Long construction, application for all geological conditions. In addition, it is possible to combine machines with the addition of dry soil with humus conditions.