What are the general tests of building foundation piles and what is pile foundation detection?

When it comes to pile foundation detection, relevant construction people are still relatively unfamiliar, what is pile foundation detection? What are the common methods for pile foundation detection? The following is the basic information of Zhongda Consulting for construction personnel to sort out the relevant pile foundation testing, the specific content is as follows:

First of all, let's understand what is pile foundation inspection?

The Foundation Structure Testing Institute includes foundation pit monitoring, pile foundation testing and other foundation engineering. Specific pile foundation detection (high strain, low strain change measurement and static load test), foundation pit monitoring, foundation pit support, etc.

According to the "Technical Code for Building Foundation Detection" (JGJ106-2003), the main methods of pile foundation detection include static load test, core drilling method, low strain method, high strain method, acoustic transmission method and so on.

The contents of the pile foundation ultrasonic testing method are as follows:

Ultrasonic of pile foundation is to detect the compactness of the concrete of the pile and the integrity of the pile. The principle is very simple, that is, the ultrasonic wave (emission tube) is used to pass through the concrete section of the pile body, and the absorption tube absorbs the ultrasonic wave, according to the distance between the two (the distance between the pipes embedded in the pile head is measured manually), and the time of the sound wave (the instrument is directly drawn on the paper) to judge the density of the concrete. If the pile concrete is ideal, then the waveform drawn is basically the same; If there is a lack of compactness somewhere in the pile (or there is sediment in the concrete), then when the ultrasonic measurement reaches this point, the time will be shortened, and the waveform drawn will be very narrow, and the surveyor can immediately judge that there is a problem with the concrete here.

1. For the precast piles (including driven prefabricated piles and static press-in prefabricated piles) and steel piles, the elevation of the pile top, the deviation of the pile position, the depth of driving (or static pressure), the hammer stop standard, and the bearing layer at the end of the pile should be inspected.

2. For cast-in-place piles, the elevation of the pile top, the deviation of the pile position, the quality of the pile body, and the bearing layer at the end of the pile should be detected.

3. For manually dug piles, the excavation size, whether there is false soil, geotechnical conditions, and the bearing layer at the end of the pile should be inspected. For large-diameter rock-socketed piles with single columns and single piles, whether there are cavities, fracture zones, weak interlayers and other adverse geological processes within the depth range of 3d or 5m under the pile should be tested according to the lithology. If necessary, the in-situ load test of the rock foundation of the bearing layer at the end of the pile and the friction test of the pile side should be carried out, and the number of test piles should not be less than 1% of the total piles under the same conditions, and not less than 3.

Pile foundation detection, divided into pile foundation before construction and after construction detection: before construction, the test pile detection that provides the basis for design, mainly determines the ultimate bearing capacity of a single pile; After construction, the engineering pile detection that provides a basis for acceptance, mainly carries out the single pile bearing capacity and pile integrity detection.

Summary. Hello, I have seen your question and am sorting out the answer, please wait a while What tests do pile foundations need to do?

Hello, I have seen your question, and I am sorting out the answer, please wait for a while After the pile foundation is done, it is usually necessary to check whether the bearing capacity of the pile foundation meets the specifications, how to check the structural integrity of the pile foundation, how about its bright celery deformation characteristics, what is the load sharing ratio of the pile soil, and what will the impact of the pile foundation on the environment. For specific items that need to be tested, we can consult relevant professionals.

The pile foundation testing items include static load testing of bearing capacity of foundation and composite foundation, bearing capacity of pile foundation, integrity testing of pile body, and locking force detection of anchor rods.

According to the "Technical Specification for Building Pile Foundation Detection", the main methods of pile foundation detection include static load test, core drilling method, low strain method, high strain method, acoustic transmission method and so on. The static load test is currently recognized as the most direct and reliable test method for detecting the vertical compressive bearing capacity of foundation piles. However, in engineering practice, it is found that the problem of the reference pile is sometimes ignored by the inspectors, and it is easy to have the problem of insufficient penetration depth of the reference pile and displacement during the test process.

This method has the characteristics of science, intuitiveness and practicality, and is widely used in the detection of concrete cast-in-place piles. A complete and successful core detection can obtain the pile length, the concrete strength of the pile, the thickness of the sediment at the bottom of the pile and the integrity of the pile, and determine or identify the geotechnical properties of the bearing layer at the end of the pile.

Precautions for foundation pile piling

1. Before piling the foundation pile, we should check the prefabricated pile, for example, we should check the quality inspection record and certificate of the product. If cracks appear in the precast pile, the length and depth of the cracks should be carefully checked to see if they meet the requirements of the relevant codes. If there are cracks in the precast piles, we should repair them.

If there are longitudinal cracks in the prefabricated piles, we should replace them in time.

2. The pile position should be inspected before the foundation pile is driven, and the depth of the pile position should meet the requirements of the construction design, and the drainage ditch should be set up around the construction site to meet the requirements of three links and one level. When driving piles, pay attention to the piling sequence and try to avoid the movement of adjacent piles during piling.

3. After the foundation pile is driven, do not immediately carry out the next process, we must first accept the pile foundation. The compressive bearing capacity of the pile foundation can be checked by the static load test method, and the structural integrity of the notched pile foundation can be checked by the low strain dynamic test method to ensure that the pile foundation meets the design requirements before the next step of construction.

After the pile foundation is done, it is usually necessary to check whether the bearing capacity of the pile foundation meets the specifications, check the structural integrity of the pile foundation, how its deformation characteristics, how the load sharing ratio of the pile soil, and what impact the pile foundation will have on the environment. For specific items that need to be tested, we can consult relevant professionals.

Second, what should be paid attention to in piling.

1. Before piling, we must first inspect the prefabricated piles, for example, we need to check the quality inspection records of the products, the certificate of conformity, etc. If there are cracks in the prefabricated pile, we should carefully check whether the length and depth of the cracks meet the requirements of the relevant specifications, and we must repair the cracks in the prefabricated pile. If there is a longitudinal crack in the prefabricated pile, everyone should replace it in time.

2. Before we drive the pile, we should check the pile position to ensure that the depth of the pile ambush tour meets the requirements of the construction design, and we should set up drainage ditches around the construction site to meet the requirements of three links and one level. When driving piles, we should pay attention to the order of piling and try to avoid the situation that causes the movement of adjacent piles during the piling process.

3. After the piling is over, we should not immediately carry out the next process construction, we must first test and accept the pile foundation, we can check the compressive bearing of the pile foundation through the static load test method, and the structural integrity of the gap pile foundation through the low strain change measurement method. Ensure that the pile foundation meets the design requirements before proceeding to the next step of construction.