Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a negative pressure water leakage detection and judgment method for an underground building concrete structure.
The technical scheme of the invention is as follows:
a negative pressure water leakage detection and judgment method for an underground building concrete structure comprises the steps of selecting a plurality of detection points on the back water surface of the underground building concrete structure, arranging negative pressure detection areas at the detection points, arranging detection pressure in the negative pressure detection areas, enabling the direction of the detection pressure to be consistent with the direction from the upstream surface to the back water surface, enabling the detection pressure to reach a specified pressure value for a plurality of times, measuring and recording the leakage condition of the detection points, and judging the waterproof quality of the detection points according to the properties and the leakage condition of the detection points.
According to the method for detecting and judging the negative pressure water leakage of the underground building concrete structure, the negative pressure detection area is provided with the vacuum chamber, the vacuum chamber is connected with the vacuum pump through the manual valve, and the vacuum pressure gauge is arranged between the vacuum chamber and the vacuum pump.
Further, the vacuum chamber is a vacuum chuck of 500mm × 400 mm.
The negative pressure water leakage detection and judgment method for the underground building concrete structure comprises the following steps of
(1) The part with the maximum water pressure bearing capacity in the underground building concrete structure;
(2) The position with the largest stress deformation in the underground building concrete structure;
(3) Constructing a joint;
(4) Early-cracked fractures;
(5) And the maximum bending moment in the underground building concrete structure.
When the underground building concrete structure is a long longitudinal structure, 3 detection points are arranged at intervals of 100m, or every 1000m 2 Is provided with 3 said detection points.
In the method for detecting and judging negative pressure water leakage of the underground building concrete structure, the specified pressure value is equal to the difference between the designed highest water level water pressure of the underground building concrete structure and the existing underground water level water pressure.
Further, the maximum value of the specified pressure value is 0.2-0.5Mpa.
Still further, the maximum value of the prescribed pressure value is 0.5Mpa.
According to the method for detecting and judging the negative pressure water leakage of the underground building concrete structure, the maximum pressure value of the detected pressure is maintained for 10 minutes or more.
In the method for detecting and judging negative pressure water leakage of the concrete structure of the underground building, the detection points are divided into four stages according to the activity frequency of the personnel, the first stage detection point is a place where the personnel stay for a long time, the second stage detection is a place where the personnel frequently move, the third stage detection point is a place where the personnel temporarily move, and the fourth stage detection point is a place where no personnel move,
the qualified detection standard of the first-stage detection point is as follows: the negative pressure detection area has no water leakage point, and the surface of the negative pressure detection area has no wet trace;
the qualified detection standard of the second-stage detection point is as follows: the negative pressure detection area has no water leakage point, and a small amount of wet traces are arranged on the surface of the negative pressure detection area;
the qualified standard of the third-stage detection point is as follows: a small number of water leakage points are arranged in the negative pressure detection area, and the negative pressure detection area is provided with wireless water leakage points;
the qualified detection standard of the fourth-stage detection point is as follows: the negative pressure detection area has no linear water leakage point and no silt leakage.
Further, the qualified second-stage detection point needs to meet the following requirements at the same time: the total wet trace area is not more than one thousandth of the total water-facing area; any 100m 2 The moisture trace point in the upstream surface is not more than 2; the maximum area of a single wet trace point is not more than 0.1m 2 。
Further, the third detection point is qualified when being detected, and the requirements that: any 100m 2 The total number of the water leakage points and the wet trace points on the upstream face is not more than 7; the maximum water leakage amount of a single water leakage point is not more than 2.5L/d; any 100m 2 The water leakage area in the water-facing surface is not more than 0.3m 2 。
Further, the qualified requirements of the fourth-stage detection point are met at the same time: the average water leakage of the engineering is not more than 2L/(m) 2 D); any 100m 2 The average water leakage of the upstream face is not more than 4L/(m) 2 .d)。
According to the scheme, the invention has the beneficial effects that the negative pressure detection area is arranged on the back surface of the concrete structure of the underground building, the pressure from the upstream surface to the back surface is applied on the back surface, so that the underground water on the upstream surface is pressed to the concrete structure of the underground building to gush, the concrete structure is enabled to bear the load equivalent to the design pressure under the condition that the underground water level does not meet the detection requirement, the detection requirement equivalent to the detection condition and the design condition is met, the real water leakage prevention capability of the concrete structure of the underground building is obtained, the waterproof quality detection of the solid engineering is completed, the engineering leakage problem is rectified before acceptance check, the labor cost for leaking stoppage and the waste of resource materials are reduced, and the economic benefit and the social benefit of the engineering are improved.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "disposed" or "connected" to another element, it can be directly or indirectly disposed on the other element. The terms "top," "bottom," "inner," "outer," and the like refer to an orientation or position based on what is shown in the figures, which is for convenience of description only and is not to be construed as limiting the present disclosure. The meaning of "plurality" is two or more unless specifically limited otherwise. As understood by those skilled in the art, pressure is herein expressed as force per unit area, i.e., pressure.
A negative pressure water leakage detection and judgment method for an underground building concrete structure is characterized in that as shown in figure 1, a plurality of detection points 1 are selected on the back water surface of the underground building concrete structure, a negative pressure detection area is arranged at the detection points 1, detection pressure is arranged in the negative pressure detection area, the direction of the detection pressure is consistent with the direction from the upstream surface to the back water surface, the detection pressure lasts for a plurality of times after reaching a specified pressure value, the leakage condition of the detection points 1 is measured and recorded, and the waterproof quality of the detection points 1 is judged according to the property of the detection points 1 and the leakage condition.
Under the condition that the concrete structure has no penetrating crack, the determining factor of the water leakage problem is the compactness of the concrete structure and the water pressure of the upstream face. When the compaction degree of the concrete structure and the water pressure of the upstream face are in a balanced position, the concrete structure cannot leak water, and if the compaction degree of the concrete structure is weaker than the water pressure of the upstream face, the concrete structure leaks water. On the contrary, even if the concrete structure has cracks, the cracks are non-penetrating cracks, and if the compaction degree of the concrete structure is higher than the water pressure of the upstream face, the water leakage phenomenon does not occur at the parts.
The invention sets a negative pressure detection area on the back surface of the underground building concrete structure, applies continuous pressure from the upstream surface to the back surface on the back surface, supplements the pressure difference between the underground water and the designed pressure caused by insufficient water level, simultaneously attracts the underground water from the upstream surface to the back surface, if the compactness of the concrete structure is insufficient, the underground water can form wet traces, even water leakage points, and if the compactness of the concrete structure is insufficient, linear water leakage points can be formed. Therefore, after the negative pressure is applied to the back surface for a certain time, the waterproof quality of the concrete structure at the position can be judged through the leakage condition of the back surface.
The specific detection standard and detection requirement of the negative pressure water leakage detection method are as follows:
1. detection point
On the basis of the same construction process, representative parts are selected as sampling samples, and different main parts are required to have a certain proportion. Because the negative pressure water leakage detection method is to apply negative pressure manually to complement the deficiency of the original underground water pressure, and the pressure born by the concrete structure is the same as the design pressure, the position which has the highest design pressure or the highest water bearing pressure and is provided with the upstream surface outside is selected, and the concrete steps are as follows:
(1) The part with the maximum water pressure in the underground building concrete structure;
(2) The maximum stress deformation position in the concrete structure of the underground building;
(3) Constructing a joint;
(4) Early-cracked fractures;
(5) The place with the largest bending moment in the concrete structure of the underground building.
The negative pressure is applied to the back water surface, so that the concrete structure bears the same load as the designed pressure, and if the concrete structure is greatly deformed or cracks under the load pressure, the compaction degree of the concrete structure is influenced, so that the part with the largest stress or the original crack is selected in the selection of the detection point 1. Under the condition of bearing load at the maximum stress, the deformation is large, cracks are easy to appear, and leakage is caused, such as the middle parts of the plate and the wall. The original crack parts such as the (3) construction joint and the (4) early-stage cracked crack are both original cracks of a concrete structure, and the concrete structure is easy to crack again under load after repair or joint filling in the later stage.
In the long and longitudinal structure of underground buildings, namely the ratio of the length to the width is very large, the structures with large transverse rigidity and small longitudinal rigidity, such as underground buildings of tunnels, subways, underground stations, shared pipe galleries and the like, are caused, and the concrete structure of the buildings needs to be provided with 3 detection points 1 at intervals of 100m at least or every 1000m 2 The upstream face of (3) is provided with a detection point (1).
2. Detecting pressure
After the detection pressure is applied to the back water surface, the pressure borne by the detection point 1 is equal to the water pressure of the designed highest water level, so the detection pressure is equal to the difference between the water pressure of the designed highest water level of the concrete structure and the water pressure of the existing underground water level. According to design specifications, the water pressure is equal to hydrostatic pressure, the underground buildings such as underground stations and the like may be larger but in a receivable range, and the calculation of the pressure of the water head can be reduced during the calculation of the tunnel structure. The concrete numerical value can be adjusted according to the requirements of actual engineering, so that the concrete structure can bear the load equivalent to the water pressure of the designed highest water level.
Because the water pressure born by the structure is related to the height of the water level above the structure along with the burial depth of the structure, after the detection point 1 is selected, the detection pressure needs to be judged according to the actually selected detection point 1 structure, so that the size of the detection pressure is adjusted, particularly, the influence of the existing water level height, such as the deepest burial depth of the bottom plate 6, the largest water pressure born by the bottom plate, the smallest burial depth of the top plate 5 and the smallest water pressure on the same cross section is adjusted.
In one embodiment, the maximum value of the predetermined pressure is 0.2-0.5MPa.
In one embodiment, the specified pressure value is 0.5Mpa maximum.
3. Time of detection
Since the application of the negative pressure at the inspection point 1 is a gradual pressurization process, the inspection pressure is maintained at the predetermined pressure value for 10 minutes or more for obtaining the optimum inspection effect, and the inspection time may be as long as 30 minutes from the preparation to the end of the inspection process in consideration of the leakage capability of the structure, etc. When sampling detection is carried out, as the whole space of the structure is sufficient, the multipoint detection can be carried out simultaneously as long as equipment and personnel are allowed, and the whole structure and the detection result are not influenced.
4. Waterproof quality detection standard
In the present invention, the water leakage phenomenon is divided into:
(1) No wet mark exists;
(2) No water leakage point and wet trace;
(3) Water leakage points are formed, and linear water leakage does not occur at the water leakage points;
(4) The water leakage point is linear water leakage and carries silt.
Referring to the subway specification, detection points are divided into four stages according to the activity frequency of people, the first-stage detection point is a place where people stay for a long time, the second-stage detection point is a place where people often move, the third-stage detection point is a place where people temporarily move (first-stage combat readiness engineering), the fourth-stage detection point is a place where no people move, and the waterproof quality requirements corresponding to areas of different levels are different, so that the corresponding detection qualified standards are different. The specific qualification criteria are as follows:
(1) The qualified detection standard of the first-stage detection point is as follows: the negative pressure detection area has no water leakage point, and the surface of the negative pressure detection area has no wet trace.
(2) The qualified detection standard of the second-stage detection point is as follows: the negative pressure detection area has no water leakage point, and a small amount of wet traces are on the surface of the negative pressure detection area.
(3) The qualified standard of the third-stage detection point is as follows: the negative pressure detection area has a small amount of water leakage points, and the negative pressure detection area has no wireless water leakage points.
(4) The qualified detection standard of the fourth-stage detection point is as follows: the negative pressure detection area has no water leakage point and no silt leakage.
The specific test results are shown below:
(1) The qualified detection of the second-stage detection point needs to be met simultaneously: the total wet trace area is not more than one thousandth of the total water-facing area; any 100m 2 The moisture trace point in the upstream surface is not more than 2; the maximum area of a single wet trace point is not more than 0.1m 2 。
(2) The qualified detection of the third detection point needs to be simultaneously satisfied: any 100m 2 The total number of the water leakage points and the wet trace points on the upstream face is not more than 7; the maximum water leakage amount of a single water leakage point is not more than 2.5L/d; any 100m 2 The water leakage area in the water-facing surface is not more than 0.3m 2 。
(3) The qualified detection of the fourth-stage detection point needs to be met simultaneously: the average water leakage of the project is not more than 2L/(m) 2 D); any 100m 2 The average water leakage of the upstream face is not more than 4L/(m) 2 .d)。
And after the pressure in the negative pressure area is stabilized at the specified pressure value for 10 minutes, the structural surface in the negative pressure area has water leakage or wet trace exceeding the qualified standard, and the detection point 1 is judged to be unqualified.
With respect to the negative pressure method detection apparatus, as shown in fig. 2, in one embodiment, a negative pressure region is created on the backside surface by the suction cup and the vacuum pump 3. Specifically, after a detection point 1 is selected on the back surface of the underground building concrete structure, a vacuum chuck 2 is fixed at the detection point 1, the vacuum chuck 2 is connected with a vacuum pump 3, and a negative pressure area is manufactured inside the vacuum chuck 2 through the vacuum pump 3. The size of the vacuum chuck 2 is 500mm × 400mm, and 0.2m can be manufactured on the back surface 2 The negative pressure region of (a). A manual valve 4 and a vacuum pressure gauge 7 are arranged between the vacuum pump 3 and the vacuum sucker 2, and the negative pressure is adjusted through the manual valve 4 and the vacuum pressure gauge 7 according to the design pressure of a concrete structure so as to be equal to the specified pressure value.
The invention adopts the negative pressure method to detect the waterproof quality of the underground building concrete structure, can complement the pressure difference that the natural condition does not reach the highest design water level pressure, enables the concrete structure to be detected under the water pressure load of the highest design water level, can find out the potential leakage problem in advance, realizes the inspection effect of the acceptance inspection of the engineering, simultaneously promotes all parties involved in the construction to improve the design and construction process, improves the waterproof quality of the entity engineering, avoids the direct loss and the indirect loss caused by the leakage water after the operation, saves a large amount of high leakage stoppage maintenance cost, has negative influence on the society by the engineering maintenance, and improves the economic benefit and the social benefit of the engineering.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.