RU2367742C1 - Method of assembled or semi-assembled multilayer water-proof structure construction on ground and method of monitoring structure contact to ground - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: group of inventions concerns construction, particularly methods of construction for embedded or semi-embedded concrete waterproof structures, such as underground passages and vehicle tunnels, and methods of structure diagnostics and monitoring both in the process of construction and operation. Comprehensive analysis of structure contact to ground is provided, preventing impact of possible structure defects on final result due to differentiated approach to definition of defect and defect border localisation by the volume of 'structure-ground' system. Effect is achieved by the method of assembled or semi-assembled multilayer concrete waterproof structure construction in ground, involving water insulation works, installation of removable shifting or stationary boarding in design position, concrete supply over boarding, operations of seismoacoustic definition of structure contact to ground: mechanical vibration exciting in constructional structure after the concrete reaches stripping strength, measurement of vibration parametres in monitored surface point and detection of areas with measured parametre gradient. To provide verification of quality of structure contact to ground, ultrasonic monitoring of concrete structure defect presence and depth (e.g. for cavities and/or segregation) is performed additionally in detected defect areas or preliminarily. In the absence of defects contact quality defined by seismoacoustic method is considered reliable, in the presence of defects, they are eliminated by consolidating or fixating mix feed to defect area and repeated exciting of mechanical vibrations in the constructional structure and vibration parametre measurement are performed in the same or other monitored surface point, preferably in the area of detected defect. Ground contact monitoring method for multilayer waterproof concrete structures under construction or in operation involves conventional division of structure surface into sectors within which concrete thickness and insulation thickness parametres are equal, with further implementation of seismoacoustic quality monitoring of structure contact to ground: mechanical vibration exciting in the structure, vibration parametre measurement in monitored surface point, and detection of areas with measured parametre gradient within the selected sector. To provide verification of quality of structure contact to ground, monitoring of concrete structure defect presence and depth (e.g. for cavities and/or segregation) is performed additionally in detected defect areas or preliminarily, e.g. by ultrasonic method. In the absence of defects contact quality defined by seismoacoustic method is considered reliable, in the presence of defects, repeated assessment of quality of structure contact to ground by seismoacoustic method is performed, followed by verification of ground contact quality definition by ultrasonic method involving monitoring of defect presence and depth in the concrete structure itself in another monitored surface point, preferably within the area of detected defect. Vibration excitation and measurements are performed by non-destructive method at one side of constructional structure.

EFFECT: maintenance of constructional structure operation according to its design model, by providing reliable and lasting operation of constructional structures placed in ground, due to enhanced verification of quality of structure contact to ground.

2 cl, 2 dwg

Description

The group of inventions relates to the field of construction, in particular, to methods for erecting concrete buried or partially buried waterproofing structures in the ground, such as underpasses, transport tunnels, as well as to methods for diagnosing and monitoring their condition both during construction and during operation.

There is a method of erecting building structures buried in the ground, in which the concrete mixture is fed to the formwork and mixed therein, which ensures its necessary density and the absence of voids unfilled with the concrete mixture (SU No. 620616, 1978).

The closest known method is the construction of a prefabricated or precast-monolithic concrete multilayer waterproofed building structure in the ground, including waterproofing work, installing removable removable or fixed formwork in the design position, feeding concrete formwork for formwork and determining the quality of contact of the building structure with the ground (RU No. 2181418, 2002).

A known system for monitoring the state of a building structure, the sensors of which are connected to a computer signal processing system (RU No. 2049231, 1995).

For diagnostics, as a rule, ultrasonic and radar defect monitoring systems adopted as a prototype are used that do not allow reliable determination of the contact quality at the lining-ground boundary due to strong distortion of the parameters of acoustic and electromagnetic signals passing through multilayer structures consisting of inhomogeneous materials, especially such as concrete and reinforced concrete (Ermolov I.N., Lange Yu.V. Ultrasonic control. - M.: "Mechanical Engineering", 2004).

Common disadvantages of the methods described above is the incompleteness of the analysis of the building structure due to the impossibility of a differentiated approach to determining the location of the defect, its boundaries according to the volume of the "building structure-soil" system, which does not allow to reliably judge the quality of its state of contact with the soil. So, in the process of determining the state of contact of an underground building structure with soil by the seismoacoustic method from the inside, it is practically impossible to unambiguously determine at what depth from its inner surface the void discovered by this method is located: whether it is in the body or behind it - at the border of contact with the soil. This is especially true for multilayer reinforced concrete structures, which are the tray parts of the object under examination (when layering concrete).

As a result of this, voids that are not filled with soil or concrete may form, which leads to a change in the existing loads (a change in their design), to a violation of waterproofing and leakage, as well as to a violation of the design dynamics of the operation of the "building structure-ground" system, which is negative affects the reliability and durability of the building structure.

The technical task of the invention is to ensure the working conditions of building structures in accordance with their design scheme, i.e. the elimination of the above disadvantages by ensuring the reliability and durability of building structures located in the ground by increasing the reliability of determining the quality of their contact with the ground. This is ensured by the completeness of the analysis of the contact of the building structure with the soil, eliminating the influence of possible defects of the building structure itself on the final result due to the differentiated approach to determining the location of the defect and its boundaries in terms of the volume of the “building structure - soil” system.

This is achieved by the fact that:

- in the method of erecting in the soil a prefabricated or precast-monolithic concrete multilayer waterproofed building structure, including waterproofing work, installing removable removable or fixed formwork in the design position, feeding concrete formwork, the seismic-acoustic method for determining the quality of contact of a building structure with the soil: excitation after a set of concrete stripping strength of mechanical vibrations of a building structure, measuring their parameters at a controlled point surfaces and the identification of zones with a gradient of measured parameters, moreover, to ensure the reliability of the quality of contact of the building structure with the soil, additionally in the identified zones of defects or pre-carry out ultrasonic monitoring of the presence and depth of its defects directly in the concrete structure, for example voids and / or delaminations, in the absence of which the contact quality of the building structure with the soil determined by the seismoacoustic method is considered reliable, and if any, eliminate external defects by feeding a hardening or fixing mixture into the zone of their detection and repeatedly producing the indicated excitation of mechanical vibrations of the building structure and measuring their parameters at the same or another controlled point on the surface, preferably in the zone of the detected defect;

- in a method for monitoring the contact state of erected or operated concrete multilayer waterproofing building structures in the soil, including conditionally dividing its surface into sections, within which it has equal parameters for concrete thickness and waterproofing thickness, followed by the operation of the seismic-acoustic method for determining the contact quality of a building structures with soil: excitation of mechanical vibrations of a building structure, measurement of their parameters in a controlled t surface point and identification of zones with a gradient of measured parameters within the selected area, and to ensure the reliability of the contact quality of the building structure with the soil, additionally or preliminary, for example, an ultrasound examination at the controlled surface point of the presence and depth of its defects directly in the concrete structure, for example voids, is carried out and / or bundles, in the absence of which the contact quality of the building structure determined by the seismic-acoustic method with soil is considered reliable, and if available, the indicated determination of the quality of contact between the building structure and the soil by the seismic-acoustic method is repeated and the reliability of the result of determining the quality of contact by the ultrasonic method is checked by monitoring the presence and depth of its defects directly in the concrete structure at another controlled surface point, preferably the zone of the detected defect, and the excitation of oscillations and measurements are made by a non-destructive method on the one hand with constructional design.

Figure 1 - state of the contact "lining-soil" distillation tunnel of the 2nd path according to the results of seismic inspection at PK187 + 21-PK188 + 10.7 between the metro stations Teply Stan and Yasenevo. Rectangular shape. (PC - picket, marking along the length of the tunnel, 1 picket is 100 m).

Figure 2 - the location of the "tapes" of ultrasonic scanning of the void zones detected by the seismic-acoustic method, at PK187 + 21 - PK188 + 10.7 between the metro stations Teply Stan and Yasenevo. Rectangular shape.

A method of erecting a prefabricated or precast-monolithic concrete multilayer waterproofed building structure in the ground includes waterproofing works to prevent the penetration of ground or soil water into the structure. As a rule, waterproofing is multilayer on the outside of the building structure. The erection of the building structure is carried out by installing removable removable or non-removable formwork in the design position and supplying concrete form for the formwork, followed by formwork. The operations of the seismic-acoustic method for determining the quality of contact of a building structure with the soil are carried out by excitation of concrete vibrations of the building structure after the concrete is removed from the stripping strength, during which their parameters are measured at a controlled point on the surface. Additionally or pre-monitor, for example, ultrasound, the presence and depth of defects in the building structure, such as voids and / or delaminations, directly in the concrete building structure. In the absence of defects, the quality of contact between the building structure and the soil determined by the seismic-acoustic method is considered reliable, and if there is, they eliminate the detected defects by supplying a hardening or fixing mixture to the zone of their detection and repeat the indicated excitation of mechanical vibrations of the building structure and measuring their parameters in the same or other controlled the point of the surface that is chosen, preferably in the coverage area of the previous measurement.

The implementation of the above method provides a method for monitoring the contact state of erected or operated concrete multilayer waterproofing building structures in the soil, which includes the operations of the seismic-acoustic method for determining the quality of contact of the building structure with the soil: excitation of mechanical vibrations of the building structure and measuring their parameters - amplitude-phase-frequency characteristics in controlled surface point. Additionally (i.e. after seismic-acoustic examination) or previously (i.e. before it) an ultrasound examination is carried out at a controlled point on the surface for the presence and depth of its defects directly in the concrete structure, which, as a rule, include voids and / or bundles. Further, in the absence of defects, the quality of the contact of the building structure with the soil, determined by the seismic-acoustic method, is considered reliable, and if available, the indicated determination of the quality of the contact of the building structure with the soil by the seismic-acoustic method is repeated and the reliability of the result of determining the quality of the contact is evaluated, for example, by ultrasonic testing the presence and depth of the location directly in the concrete structure of its defects at another controlled point on the surface, and all Impacts and measurements are made by the non-destructive method on one side of the building structure, processing the obtained data on the state of the contact zone and applying them to the scan of the surveyed section of the building structure, which allows you to visually - with building maps or on the monitor, get a scanned image of the distribution of defective areas over the area of the building structure .

This monitoring method eliminates the influence of defects in the building structure itself, including defects in its waterproofing, on the reliability and boundaries of the identified defects in its contact with the soil, the presence of which can lead to the destruction of the building structure due to a change in the design conditions of its operation.

Thus, the method of monitoring the quality of contact of underground structures with soil includes the following operations:

- determination by the seismic-acoustic method of the quality of contact of the multilayer structure of the underground structure, for example, the chute part of the distillation subway tunnel with the ground;

- building contact quality maps on a scan of the object under examination based on the results of seismic-acoustic monitoring;

- analysis of the results of seismic-acoustic inspection of the quality of the contact and the selection of control zones by the ultrasonic method;

- ultrasound examination (scanning) of selected areas with a flaw detector, for example A 1220 MONOLITH;

- processing of the results of ultrasound scanning and their analysis;

- Correction of quality maps of the “lining-soil” contact on the scan of the examined object according to the results of ultrasonic testing with the specification of the depth of the location of the void zones detected during the survey by the seismic-acoustic method.

In this regard, for the examination of buried building structures, it was decided to combine the seismic-acoustic method and the ultrasonic method, implemented, for example, in the A 1220 MONOLIT flaw detector.

The seismic-acoustic method for assessing the state of contact of the lining with the soil under the base is based on the analysis of the parameters of the damped seismic-acoustic vibrations of the surface of the lining caused by mechanical impulse action. To make a decision about the state of contact, the following parameters of lining vibrations were used:

- oscillation decay time;

- the initial amplitude of the oscillations;

- damping coefficient of oscillations.

In the course of experimental studies conducted at the research center of TM "TM" and on physical models simulating the different state of contact of the building structure with the soil, it was found that good contact is characterized by a low initial amplitude of vibrations of the lining surface, their rapid attenuation and, therefore, a high attenuation coefficient for due to the presence of attached soil mass. In the case of poor contact, lining vibrations have a high initial amplitude and decay for a relatively long time.

Experimental studies at the research center "TM" also made it possible to establish that the reliability of the detection of voids by the seismic-acoustic method is 55-60%, which does not satisfy the initial conditions for the application of the method also due to the significant length of the buried building structure.

Assessment of the state of contact of a building with soil is carried out in two stages:

- record and systematization of the source data at the survey object;

- automated data processing.

To record and systematize vibrations of the surface of the structure, a set of equipment and software was used, which includes a signal recording system based on a portable two-channel seismic station. The signal recording system also includes a sensing element connected to the seismic station by means of a coaxial cable - an electrodynamic seismic receiver, for example, of the GS-20DX type, which perceives vibrations of the structure surface and converts them into an electrical signal. A single impact hammer created on the basis of the OMSh-1 sclerometer with a constant impact energy of 1.93 J or a measuring hammer created on the basis of a manual probe for probing RZG-2 soils with a constant energy of impact was used as a source of excitation of local vibrations of the surface of a building structure 20.8 J. The constancy of impact energy is necessary for the correct comparative analysis of signal records at various points in the building structure. All impacts exciting oscillations of the examined lining structures were applied in the direction normal to the surface of the structure. During the inspection, its surface was divided into sections so that within each section the lining parameters, such as its thickness, material, etc., remained unchanged. In each section, a regular grid formed by parallel sections consisting of several points was marked out. Then, at each point of the regular grid, several records of damped vibrations of the lining surface were made. For this, a sensitive element was installed at the marked point on the surface of the structure, the recording mode was turned on, and a strike was made on the surface in the immediate vicinity of the sensitive element.

Example

Based on the results of surveys of the object carried out by the seismic-acoustic method (for example, a rectangular distillation tunnel at PK187 + 21 - PK188 + 10.7 between the Teply Stan and Yasenevo metro stations), maps of the state of contact of the tunnel lining with the embankment soil mass in the form of plotted on the scan isolines of the contact state. Such a map of an object selected for example is presented in FIG. 2, which shows a scale (legend) that displays the state of contact “K” of the examined lining sections from the level of “no contact” to the level of “tight contact”. According to the scale, the zone of no contact (void) corresponds to the interval of contact values 0≤K <3, the zone of weakened contact corresponds to the interval of contact state values 3≤K <6 and the zone of tight contact corresponds to the interval of contact state values 6≤K≤9. The numbers affixed to the map isolines correspond to the contact status levels (numbers) of the scale. For better visualization of the map, each of the three zones of contact status - the zone of no contact, the zone of weakened contact and the zone of close contact are shaded with the corresponding color.

The technique for clarifying the depth of the void zones detected by the seismoacoustic method in the multilayer parts of the structure is as follows. On the constructed isoline maps of the object lining contact state (see Fig. 1), the areas with the voids detected by the seismoacoustic method and the transitions of the contact state to the void (across the boundary of the void zone) were selected and a survey ("tape" scan) of the selected zones was carried out using a flaw detector A 1220 MONOLITH. Later, on a computer, we analyzed the results of recording the signals of such “tapes” using the program “Introvisor 2.4”, developed by the manufacturer of flaw detector A 1220 “MONOLIT”. The location of the "tapes" of ultrasonic scanning on the constructed map of the quality of the contact "lining-soil" is shown in Fig.2. The same figure shows the results of the correction of the initial contact quality map based on the results of ultrasound examination (see the void scanned by tape No. 12).

Claims (2)

1. The method of erecting a prefabricated or precast-monolithic concrete multilayer waterproofed building structure in the ground, including waterproofing work, installing removable removable or fixed formwork in the design position, feeding concrete formwork, the seismic-acoustic method for determining the quality of contact of a building structure with the soil: excitation after a set of concrete stripping strength of mechanical vibrations of the building structure, measuring their parameters at a controlled point surfaces and the identification of zones with a gradient of measured parameters, moreover, to ensure the reliability of the quality of contact of the building structure with the soil, additionally in the identified zones of defects or pre-carry out ultrasonic monitoring of the presence and depth of its defects directly in the concrete structure, for example voids and / or delaminations, in the absence of which the contact quality of the building structure with the soil determined by the seismoacoustic method is considered reliable, and if available, eliminate obna Toughened defects by feeding a hardening or fixing mixture into the zone of their detection and repeatedly producing the indicated excitation of mechanical vibrations of the building structure and measuring their parameters at the same or another controlled point on the surface, preferably in the zone of the detected defect. 2. A method for monitoring the contact state of erected or operated concrete multilayer waterproofing building structures in the soil, including conditionally dividing its surface into sections, within which it has equal parameters for the thickness and properties of concrete and the thickness of the waterproofing, followed by seismic-acoustic method for determining the quality the contact of the building structure with the soil: the excitation of mechanical vibrations of the building structure, measuring their parameters in control at a given surface point and identifying zones with a gradient of measured parameters within the selected area, moreover, to ensure the reliability of the contact quality of the building structure with the soil, an additional or preliminary examination is carried out, for example, ultrasound at a controlled surface point of the presence and depth of its defects directly in the concrete structure, for example voids and / or delaminations, in the absence of which the quality of contact of the construction co structures with soil are considered reliable, and if available, the indicated determination of the quality of contact between the building structure and the soil by the seismoacoustic method is repeated and the reliability of the result of determining the quality of contact by the ultrasonic method is checked by monitoring the presence and depth of its defects directly in the concrete structure at another controlled surface point, preferably in the area of the detected defect, and the excitation of oscillations and measurements are made by a non-destructive method with one side of a building structure.

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