CN114396082A - Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means - Google Patents
Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means Download PDFInfo
- Publication number
- CN114396082A CN114396082A CN202111462450.9A CN202111462450A CN114396082A CN 114396082 A CN114396082 A CN 114396082A CN 202111462450 A CN202111462450 A CN 202111462450A CN 114396082 A CN114396082 A CN 114396082A
- Authority
- CN
- China
- Prior art keywords
- soil
- pile
- explosive
- nuclear power
- power plant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/08—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against transmission of vibrations or movements in the foundation soil
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/10—Miscellaneous comprising sensor means
Abstract
The invention relates to a method for testing the dynamic characteristics of a nuclear power plant pile foundation by adopting an underground explosion means, which belongs to the technical field of civil engineering structures of nuclear power plants and comprises the following steps: s1, acquiring geological survey data, and establishing a fine stratified soil model and a simplified stratified soil model; s2, calculating the maximum speed of each soil layer in the fine stratified soil model by taking the actual engineering earthquake as input; s3, calculating the vibration speed of each soil layer in the simplified soil layer model; s4, determining explosive dosage, arrangement and detonation sequence; s5, determining the arrangement of the test piles; s6, determining the test pile form, the upper balance weight and the type and the position of a built-in sensor; s7, performing site construction, drilling and embedding explosives, and manufacturing a test pile; and S8, initiating explosives, measuring the reaction of the test pile, and obtaining the dynamic characteristic of the test pile. The method provided by the invention can simulate the propagation mode of seismic waves from bottom to top and the process of transmitting the seismic waves to the pile body from soil, so that the dynamic characteristic of the nuclear power plant pile foundation in the situation of meeting the actual earthquake is obtained.
Description
Technical Field
The invention belongs to the technical field of civil engineering structures of nuclear power plants, and particularly relates to a method for testing the dynamic characteristics of a pile foundation of a nuclear power plant by adopting an underground explosion means.
Background
The nuclear power plant has high requirements on earthquake resistance and fortification, the nuclear power plant in China generally sits on hard bedrock, a flat raft foundation is generally adopted, and the nuclear power plant needs to take water for cooling and needs to be close to an economically developed area and is generally selected as a coastal plant site, so that a proper nuclear power plant site is scarce. With the further development of nuclear power plant construction and the need for nuclear power to be removed, nuclear power plants may sit on non-bedrock, even soft soil foundations. It is necessary to apply pile foundations, which are deep foundations suitable for soft and weak foundations.
In the aspect of earthquake resistance, the earthquake resistance of equipment per se is very important in addition to the earthquake resistance of a civil structure per se in a nuclear power plant. Because if the acceleration peak value at the equipment seat exceeds the equipment bearing range, the equipment can be damaged, and the safety of the nuclear power plant is damaged. Therefore, when the civil construction structure of the nuclear power plant is designed, besides the seismic capacity of the structure, the vibration response of the equipment on the floor, namely the floor response spectrum, is calculated so as to calculate whether the acceleration is within the bearable range of the equipment.
The general path of upward transmission of seismic vibrations is: foundation-structure-equipment. For the traditional flat raft foundation, whether the raft foundation slips or separates from the foundation is mainly calculated. Because its rigidity is great, raft thickness and form are similar with upper portion nuclear power plant wallboard structure, can not cause too big influence to superstructure dynamic characteristic. However, the pile foundation is composed of slender foundation piles, so that the flexibility is high; and is rigidly connected with the upper structure through a bearing platform. When seismic waves are transmitted upwards through the foundation pile, the dynamic characteristics of the structure can be changed. Therefore, the dynamic characteristics of the pile foundation of the nuclear power plant are obtained through field and field tests, and the obtained dynamic characteristics are used as input and test correction of structural seismic accounting and floor reaction spectrum calculation, and are very important for ensuring the safety of the nuclear power plant.
At present, the pile foundation in China is widely applied and has a mature testing method and a mature testing system. Most, however, have focused on the area of load bearing testing. Mainly pay attention to whether the foundation pile can meet the requirements of bearing capacity, displacement and other applicability under the static load condition. Under the earthquake condition, the foundation piles are ensured not to be damaged by earthquake acting force by a construction method of adding reinforcing bars, enlarging a section and the like. Few engineering fields need to calculate floor response spectrums for equipment seismic resistance check, so that the dynamic characteristics of pile foundations are less concerned.
In the research field, methods are also available for approximately acquiring the behavior of the pile foundation under the earthquake vibration. Pseudo-static methods such as reciprocating pile head pushing; knocking at the pile head to obtain a reflected wave; the method is that the pile head is forced to vibrate by a vibration generating device. The methods have a plurality of defects for acquiring the dynamic characteristics of the pile foundation which is concerned by the nuclear power industry: firstly, force or vibration is only applied to the pile head part exposed out of the ground surface, only the upper part of the pile body reacts, the interaction characteristic of the pile soil at the lower part is difficult to obtain, and further the main characteristic of seismic wave propagation from bottom to top cannot be simulated; secondly, vibration is generated on the pile body and is transmitted into the soil body, and the vibration of the pile foundation is caused by seismic waves which are not transmitted by the soil body; thirdly, the vibration generated by the method is often small, and the situation that the soil body enters strong nonlinearity and the pile foundation has large displacement cannot be simulated.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a method for testing the power characteristics of the pile foundation of the nuclear power plant by adopting an underground explosion means, which can obtain the power characteristics of the pile foundation of the nuclear power plant under the condition that the pile foundation is more in line with the actual earthquake.
In order to achieve the above purposes, the invention adopts the technical scheme that:
a method for testing the dynamic characteristics of a nuclear power plant pile foundation by adopting an underground explosion means comprises the following steps:
s1, acquiring geological survey data, and establishing a fine stratified soil model and a simplified stratified soil model;
s2, calculating the maximum speed of each soil layer in the fine stratified soil model by taking the actual engineering earthquake as input;
s3, calculating the vibration speed of each soil layer in the simplified soil layer model;
s4, determining explosive dosage, arrangement and detonation sequence;
s5, determining the arrangement of the test piles;
s6, determining the test pile form, the upper balance weight and the type and the position of a built-in sensor;
s7, performing site construction, drilling and embedding explosives, and manufacturing a test pile;
and S8, initiating explosives, measuring the reaction of the test pile, and obtaining the dynamic characteristic of the test pile.
Further, in the method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion means, the fine stratified soil model is used for the conventional bottom-up seismic reaction calculation in the step S1, and the soil layer division basis comprises the soil type, the density and the wave velocity; the simplified soil layer model is used for arrangement of explosives, the soil layer of the simplified soil layer model is divided into soil types, and the soil types comprise gravel soil, sand soil, silt soil, cohesive soil and artificial filling soil.
Further, in the method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by using the underground explosion means, the method for calculating the maximum speed of each soil layer in the fine stratified soil model in the step S2 specifically includes: and calculating the maximum speed of each soil layer in the fine stratified soil model by adopting an equivalent linear method in combination with the earthquake one-dimensional propagation theory.
Further, in the method for testing the dynamic characteristics of the nuclear power plant pile foundation by using the underground explosion means, the method for calculating the vibration speed of each layer in the simplified soil layer model in the step S3 specifically comprises the following steps: merging the fine soil layer models according to the simplified soil layer models, and taking the average value of each layer inside the fine soil layer models according to the vibration speed of each layer after merging.
Further, according to the method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by using the underground explosion means, in the step S4, the arrangement mode of the explosives is specifically as follows: the method comprises the steps that explosive drill holes penetrating through all soil layers are formed in the simplified soil layer model, explosive columns are arranged in the middle of the depths of the simplified soil layers in the explosive drill holes, one explosive column is arranged in the center of each layer, and the explosive columns are filled with stemming to block up-and-down transmission of gas after the explosive in the drill holes explodes.
Further, according to the method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion means, mutual influence among simplified soil layers is not considered when the explosive amount is determined in the step S4; and determining the explosive dosage according to the particle velocity equivalent principle and the distance between the explosive and the test pile.
Further, according to the method for testing the dynamic characteristics of the nuclear power plant pile foundation by using the underground explosion means, in the step S4, the initiation sequence specifically includes: and controlling the initiation sequence from bottom to top, and determining the interval time corresponding to the two explosive columns for the differential blasting according to the time required by the propagation of the seismic waves between the depths of the two adjacent simplified soil layers.
Further, in the method for testing the dynamic characteristics of the nuclear power plant pile foundation by using the underground explosion means, the arrangement mode of the test piles in the step S5 is specifically as follows:
establishing a plurality of concentric circles by taking the explosive position as a center, determining the size of each concentric circle based on the explosive radius, and arranging a first concentric circle at the position 2-3 times of the explosive radius, wherein a crushing area is arranged in the first concentric circle; arranging a second concentric circle at the position of 5-6 times of the explosive radius, wherein a cracking area is arranged inside the second concentric circle; arranging a third concentric circle at the position of 10-20 times of the explosive radius, wherein an elastic wave propagation area is arranged in the third concentric circle;
testing piles are arranged on concentric circles with different radiuses to simulate the vibration of different vibration levels; multiple groups of parallel data can be obtained simultaneously by arranging multiple groups of test piles at different positions on a concentric circle with the same radius.
Further, according to the method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion means, in the step S6, the bearing platform is arranged at the upper part of the test pile so as to simulate the bearing platform effect and the pile group effect; and adding a balance weight on the bearing platform or manufacturing a concrete balancing weight on the single pile so as to simulate the actual vertical pressure-bearing state of the test pile.
Further, in the method for testing the dynamic characteristics of the foundation of the nuclear power plant pile by using the underground explosion method, in step S6, sensors are arranged at key positions in the test pile to acquire dynamic response data, wherein the types of the sensors comprise a displacement meter and an accelerometer.
The method for testing the dynamic characteristics of the nuclear power plant pile foundation has the following remarkable technical effects:
1. by adjusting the sequence of explosive differential blasting at different depths, the propagation mode of seismic waves from bottom to top can be simulated;
2. the process that seismic waves are transmitted to the pile body from the soil can be simulated by vibrating the soil through the explosion shock waves and then driving the pile foundation;
3. the explosive contains larger energy, can drive the soil body in a large depth range to reach plasticity and large deformation stages, and better simulates the corresponding pile foundation dynamic characteristics under large earthquake;
4. the test piles can be arranged at different distances, and the simulation of earthquakes with different seismic magnitudes can be simultaneously obtained through one test; a plurality of groups of test piles are arranged on an equipotential line of the speed of the soil mass point impacted by explosion, and a plurality of groups of parallel data can be obtained at the same time so as to make better comparative study.
Drawings
FIG. 1 is a flow chart of a method for testing the dynamic characteristics of a nuclear power plant pile foundation by using an underground explosion method according to an embodiment of the invention;
FIG. 2 is a top plan view of the arrangement of explosive and test piles;
fig. 3 is a cross-sectional view showing the arrangement of explosive charges and test piles.
Detailed Description
The invention is further described with reference to specific embodiments and drawings attached to the description.
The core idea of the invention is as follows: the soil body is driven to vibrate by explosion, and then the pile foundation is extruded by the soil body to generate vibration. Therefore, the related theoretical empirical formula of explosion mechanics and explosion in soil needs to be applied.
Explosion is a very complex process, and soil mass also contains three phases of water, gas and solid, so that the explosion in the soil is not fully established with a widely applicable model at present, but the basic process is clear. Forming a permanent cavity in a soil body in a crushing area within the range of 2-3 times of the radius of the explosive; in the range of 5-6 times of explosive radius, a cracking zone is formed, and a permanent crack is formed in a soil body; and then the elastic-plastic vibration wave and the elastic wave are propagated to the outer range. According to an explosion mechanics empirical formula, the vibration reaction of the soil at different distances, such as the maximum vibration speed and the like, under the explosion of the explosive with certain mass can be predicted. Therefore, the method establishes the connection of two different vibrations of earthquake and explosion through the vibration velocity of the soil. When the seismic wave propagates from bottom to top, the stratified soil response can be simplified into the layered shear motion from bottom to top. The layered shearing movement is simulated by applying explosives on each layer to act on the soil body and further pushing the pile body to move.
Fig. 1 shows a flowchart of a method for testing the dynamic characteristics of a pile foundation of a nuclear power plant by using an underground explosion means, which comprises the following steps:
and step S1, acquiring the geological survey data, and establishing a fine stratified soil model and a simplified stratified soil model.
In this step, two stratified soil models need to be built. The first is a fine soil layer model which is used for the conventional bottom-up seismic reaction calculation, and soil layer division is more detailed according to different soil types, densities, wave velocities and the like; the second is a simplified soil layer model for arrangement of explosives, each of which represents a soil layer and is provided with only one initiating explosive column. Due to the large explosion energy, the dynamic behavior of the soil is different only when the difference of the properties of the soil is large. Therefore, the soil can be classified according to the category, such as gravel soil, sandy soil, silt soil, cohesive soil and artificial filling. If there is underground water, the division is also performed at the depth of the underground water level, and the property difference of explosion shock wave propagation is large because the saturated soil gap is filled with water.
And step S2, taking the actual engineering earthquake as input, and calculating the maximum speed of each soil layer in the fine stratified soil model.
And (5) calculating the maximum velocity in each soil layer by using the fine soil layer model established in the step S1 and combining with the earthquake one-dimensional propagation theory and an equivalent linear method. The maximum velocity in each layer of soil can be calculated by using a more sophisticated calculation tool such as EERA.
And step S3, calculating the vibration speed of each soil layer in the simplified soil layer model.
And the arrangement of the explosives is carried out by combining the simplified soil layer model, so that the fine soil layers are merged according to the simplified soil layer model, and the average value of each layer inside is taken according to the vibration speed of each layer after merging.
And step S4, determining explosive dosage, arrangement and detonation sequence.
The explosives are distributed in the middle of the depth of each simplified soil layer, and the explosives are filled among the simplified soil layers by adopting materials such as stemming and the like. The explosive adopts a columnar extension explosive package. Because each layer in the simplified model is thicker, the explosive wave front formed by the extension explosive package is mostly columnar, and fillers are arranged among the explosives. When the explosive dosage is measured and calculated, only the explosive of the layer is considered, and the mutual influence among the layers is not considered. The explosion mechanics includes empirical curves of explosive dosage, distance and soil point speed in different soil. As the distance increases, the speed decreases exponentially. Therefore, according to the particle velocity equivalence principle, the explosive amount is calculated by the distance between the explosive and the pile. The initiation sequence is controlled from bottom to top because the propagation process of seismic waves from bottom to top is simulated, and the interval time of the differential blasting of each explosive can be determined by the time required for the seismic waves to propagate between two corresponding depths and can be calculated by the shear wave velocity of the soil body. Because the soil has great volatility, a test explosion group can be arranged, namely only explosive drill holes are arranged, test piles are not arranged around the explosive drill holes, speedometers are arranged on all soil layers, and the scheme is adjusted according to the actual measurement result.
And step S5, determining the arrangement of the test piles.
Because the propagation of the explosion shock wave is circularly propagated from the center of explosion to the periphery, the parallel groups of test piles under the influence of the same earthquake can be simulated and can be arranged along the equipotential surface of the explosion vibration velocity, and the same excitation effect can be obtained. The test piles are preferably arranged outside the crushing zone and the cracking zone, for example, the simulation large earthquake can be arranged in the elastic-plastic wave propagation zone, and the simulation small earthquake can be arranged in the elastic wave propagation zone. The test piles can be arranged at different distances from the explosive core, so that the excitation effect of the earthquakes with different seismic levels can be simulated by one-time explosion and earthquake.
Step S6: the test pile form, upper counterweight, built-in sensor type and location are determined.
The test pile is consistent with the actual engineering as much as possible. As the upper structure of the nuclear power plant has high rigidity and the bottom plate is also thick, the upper part of the foundation pile can generate a large constraint effect, and therefore, a bearing platform is suitable to be manufactured on the upper part of the foundation pile so as to simulate a bearing platform effect and a pile group effect.
The lateral displacement resistance of the foundation pile changes along with the pressure of the upper part, so that a counter weight is added on a bearing platform or a concrete counter weight is manufactured on a single pile to simulate the actual vertical pressure-bearing state of the test pile.
In order to obtain the dynamic characteristics of the pile foundation, sensors such as displacement meters and accelerometers need to be embedded in the test pile to obtain dynamic response data. The sensors should be strategically placed based on the horizontal stiffness characteristics of the test pile, and the bottom-embedded end-bearing pile is prone to a kick-back point at the upper portion 1/3 where the sensors should be encrypted to avoid the inability to capture critical locations.
Step S7: and (4) performing site construction, drilling and embedding explosives, and manufacturing a test pile.
And (4) constructing according to the design and arrangement of the steps.
Step S8: and (4) detonating the explosive, and measuring the reaction of the test pile to obtain the dynamic characteristic of the test pile.
And (4) according to the differential blasting sequence designed in the previous step, sequentially detonating the explosives from bottom to top, and measuring the dynamic response data of the test pile through a sensor.
For non-bedrock nuclear power plants, when the design of a nuclear island foundation is selected as a pile foundation, the method for testing the dynamic characteristic of the pile foundation of the nuclear power plant by adopting the underground explosion method can be adopted to obtain more reliable dynamic characteristic of the pile foundation and more real response under the earthquake. The technical solution of the present invention will be described below with reference to a specific embodiment.
Firstly, acquiring geological survey data according to the steps S1-S3, and establishing a fine stratified soil model and a simplified stratified soil model; calculating the maximum speed of each fine layering by taking the actual engineering earthquake as input; and then merging the fine soil layers according to the simplified soil layer model, and calculating the vibration speed of each layer in the simplified soil layer model.
Next, the placement of the test stakes is determined. Fig. 2 shows a top view of the arrangement of the explosive charge and the test piles, see fig. 2, with different test piles arranged on the side lines of different concentric circles, centred on the location of the explosive charge. The size of the concentric circle boundary is determined by the explosive radius. Forming a soil permanent cavity generally within the range of 2-3 times of the radius of the explosive, and marking the soil permanent cavity as a first circular side line; forming a permanent soil crack within the range of 5-6 times of the radius of the explosive, and dividing the permanent soil crack into a second circular side line; the peripheral round edge line can be estimated by 10-20 times of the explosive radius. If more accurate division is needed, a trial explosion test can be firstly carried out on a free site, the maximum speed or acceleration of the soil body can be tested around the free site, and division is carried out by combining earthquake motion design parameters of the plant site.
Because the explosion power is uniformly transmitted from the center to the periphery, the vibration of different vibration levels can be simulated by arranging test piles on concentric circles with different radiuses. The excitation of different magnitude can be obtained by one underground explosion by adjusting the explosion distance. Generally, if a small earthquake is to be simulated, the soil body is still in an elastic state under the small earthquake, the explosion distance of the test pile is adjusted, and the test pile is arranged outside the area where the soil body generates plastic deformation, namely the test pile is arranged in an elastic wave propagation area. If a large earthquake is to be simulated, the soil body generates permanent plastic deformation under the large earthquake, and the explosion distance of the test pile is adjusted to be arranged between the first round edge line and the second round edge line. In special cases, if the position of the pile head and the lateral movement resistance of the pile body are considered, the pile body can be integrally arranged in the range of a first circular edge, namely, the foundation pile is pushed by utilizing larger explosion power and a generated permanent soil cavity area to obtain larger response.
Determining explosive dosage, arrangement and detonation sequence. Figure 3 illustrates the seismic effect produced by subsurface explosion simulation. Since the formation is generally layered, the deeper the buried depth, the more dense the earth in general, and the greater the bearing capacity. And filling explosives in the formed drill holes, wherein the explosives are placed according to simplified stratified soil models of the layers of the soil after the layers of the soil are merged according to properties, and one explosive is placed in the center of each layer. The explosive is filled with materials. The packing material can be made of local materials, and aims to prevent the gas from vertically spreading after the explosive column in the drilling hole explodes. Specifically, clay, rock debris, denser graded crushed stone and the like can be adopted and should be compacted as much as possible. The explosive columns are slightly detonated according to the sequence from bottom to top so as to control the difference of the explosion time of the explosive columns in millisecond or second level, thus leading the vibration of the subsoil to always precede the vibration of the subsoil so as to simulate the characteristic that seismic waves are transmitted in a layered shearing mode from bottom to top. The differential shot time interval of the explosive columns can be obtained by dividing the distance between each other by the soil layer weighted average longitudinal wave velocity.
According to the mode of arranging explosive in the drill hole, a shock wave continuously expanding from the center to the outside is propagated in each layer. The energy of the earthquake simulation device acts on the soil to drive the soil to generate particle motion and also indirectly acts on the foundation pile embedded in the soil, so that the earthquake simulation device simulates the motion of the soil-driven pile foundation under the earthquake.
The test pile form, upper counterweight and built-in sensor type and location are determined. Because vertical load-carrying is more crucial to the dynamic characteristic of pile foundation in the pile body, in fig. 2, no matter be single pile or pile group upper portion, all be provided with the counter weight. The counter weight can be set as the weight transferred by the superstructure shared by single piles or grouped piles under the constant load condition considered by the design of the pile foundation. The pile group upper portion can set up the cushion cap, not only can cooperate and cover more counter weights, moreover because the cushion cap is thicker, the big outer bending resistance of rigidity in the face is stronger, and it links together a plurality of foundation pile heads for single pile head is difficult to be crooked under the side state of moving, still can simulate the effect of inlaying solid to the pile head of the great cushion cap of rigidity in the plane in the actual engineering from this. Therefore, the foundation pile with certain vertical bearing can reflect the real situation when horizontally vibrating. On one hand, the actual local concrete of the pile body is wrapped by the surrounding soil body to generate lateral resistance and friction force, and also has the downward force of the upper structure, and the vertical force is applied to ensure that the pile body is in a more real three-dimensional stress state; on the other hand, the pile body is long, the flexibility is high, the secondary effect when the pile foundation side shift is large is easier to embody when the vertical force is applied, and the weak link is more truly embodied.
And finally, performing field construction according to the design and arrangement of the steps, drilling and embedding explosives, manufacturing a test pile, sequentially detonating the explosives from bottom to top according to the differential blasting sequence, and obtaining pile foundation dynamic response data through a sensor.
The method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion method can simulate the propagation mode of seismic waves from bottom to top by adjusting the sequence of explosive differential blasting at different depths; the process that seismic waves are transmitted to the pile body from the soil can be simulated by vibrating the soil through the explosion shock waves and then driving the pile foundation; the explosive contains larger energy, can drive the soil body in a large depth range to reach plasticity and large deformation stages, and better simulates the corresponding pile foundation dynamic characteristics under large earthquake; the test piles can be arranged at different distances, and the simulation of earthquakes with different seismic magnitudes can be simultaneously obtained through one test; a plurality of groups of test piles are arranged on an equipotential line of the speed of the soil mass point impacted by explosion, and a plurality of groups of parallel data can be obtained at the same time so as to make better comparative study.
The above-described embodiments are merely illustrative of the present invention, which may be embodied in other specific forms or in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims should be construed to be included therein.
Claims (10)
1. A method for testing the dynamic characteristics of a nuclear power plant pile foundation by adopting an underground explosion means comprises the following steps:
s1, acquiring geological survey data, and establishing a fine stratified soil model and a simplified stratified soil model;
s2, calculating the maximum speed of each soil layer in the fine stratified soil model by taking the actual engineering earthquake as input;
s3, calculating the vibration speed of each soil layer in the simplified soil layer model;
s4, determining explosive dosage, arrangement and detonation sequence;
s5, determining the arrangement of the test piles;
s6, determining the test pile form, the upper balance weight and the type and the position of a built-in sensor;
s7, performing site construction, drilling and embedding explosives, and manufacturing a test pile;
and S8, initiating explosives, measuring the reaction of the test pile, and obtaining the dynamic characteristic of the test pile.
2. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by the underground explosion means as claimed in claim 1, wherein the fine stratified soil model is used for the conventional bottom-up seismic reaction calculation in the step S1, and the soil layer division thereof is based on the factors including soil type, density and wave velocity; the simplified soil layer model is used for arrangement of explosives, the soil layer of the simplified soil layer model is divided into soil types, and the soil types comprise gravel soil, sand soil, silt soil, cohesive soil and artificial filling soil.
3. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by adopting the underground explosion means as claimed in claim 2, wherein the method for calculating the maximum speed of each soil layer in the fine stratified soil model in the step S2 is specifically as follows: and calculating the maximum speed of each soil layer in the fine stratified soil model by adopting an equivalent linear method in combination with the earthquake one-dimensional propagation theory.
4. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by adopting the underground explosion means as claimed in claim 3, wherein the method for calculating the vibration speed of each layer in the simplified soil layer model in the step S3 is specifically as follows: merging the fine soil layer models according to the simplified soil layer models, and taking the average value of each layer inside the fine soil layer models according to the vibration speed of each layer after merging.
5. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by adopting the underground explosion means as claimed in any one of claims 1 to 4, wherein the arrangement mode of the explosives in the step S4 is as follows: the method comprises the steps that explosive drill holes penetrating through all soil layers are formed in the simplified soil layer model, explosive columns are arranged in the middle of the depths of the simplified soil layers in the explosive drill holes, one explosive column is arranged in the center of each layer, and the explosive columns are filled with stemming to block up-and-down transmission of gas after the explosive in the drill holes explodes.
6. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by adopting the underground explosion means as claimed in claim 5, wherein the mutual influence among the simplified soil layers is not considered when the explosive amount is determined in the step S4; and determining the explosive dosage according to the particle velocity equivalent principle and the distance between the explosive and the test pile.
7. The method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion means as claimed in claim 6, wherein the initiation sequence in the step S4 is specifically as follows: and controlling the initiation sequence from bottom to top, and determining the interval time corresponding to the two explosive columns for the differential blasting according to the time required by the propagation of the seismic waves between the depths of the two adjacent simplified soil layers.
8. The method for testing the dynamic characteristics of the nuclear power plant pile foundation by adopting the underground explosion means as claimed in claim 1, wherein the arrangement mode of the test piles in the step S5 is specifically as follows:
establishing a plurality of concentric circles by taking the explosive position as a center, determining the size of each concentric circle based on the explosive radius, and arranging a first concentric circle at the position 2-3 times of the explosive radius, wherein a crushing area is arranged in the first concentric circle; arranging a second concentric circle at the position of 5-6 times of the explosive radius, wherein a cracking area is arranged inside the second concentric circle; arranging a third concentric circle at the position of 10-20 times of the explosive radius, wherein an elastic wave propagation area is arranged in the third concentric circle;
testing piles are arranged on concentric circles with different radiuses to simulate the vibration of different vibration levels; multiple groups of parallel data can be obtained simultaneously by arranging multiple groups of test piles at different positions on a concentric circle with the same radius.
9. The method for testing the dynamic characteristics of the pile foundation of the nuclear power plant by adopting the underground explosion means as claimed in claim 8, wherein a bearing platform is arranged at the upper part of the test pile in the step S6 to simulate the bearing platform effect and the pile group effect; and adding a balance weight on the bearing platform or manufacturing a concrete balancing weight on the single pile so as to simulate the actual vertical pressure-bearing state of the test pile.
10. The method for testing the dynamic characteristics of the foundation of the nuclear power plant pile by the underground explosion method according to claim 1, wherein sensors of the types including a displacement meter and an accelerometer are arranged at key positions of the test pile in the step S6 to obtain dynamic response data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111462450.9A CN114396082A (en) | 2021-12-02 | 2021-12-02 | Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111462450.9A CN114396082A (en) | 2021-12-02 | 2021-12-02 | Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114396082A true CN114396082A (en) | 2022-04-26 |
Family
ID=81225287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111462450.9A Pending CN114396082A (en) | 2021-12-02 | 2021-12-02 | Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114396082A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105425281A (en) * | 2016-01-19 | 2016-03-23 | 北京理工大学 | Method for determining distributed explosive source triggering parameters |
| CN105676273A (en) * | 2016-01-19 | 2016-06-15 | 北京理工大学 | Design method for high-energy high-frequency explosive seismic source |
| CN108166544A (en) * | 2018-01-11 | 2018-06-15 | 山东大学 | A kind of test pile working mechanism and technique effect comprehensive detection system and method |
| CN109612356A (en) * | 2018-12-19 | 2019-04-12 | 中国地质大学（武汉） | The acquisition methods of concrete duct dynamic response characteristics are closed on when excavation of foundation pit explosion |
-
2021
- 2021-12-02 CN CN202111462450.9A patent/CN114396082A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105425281A (en) * | 2016-01-19 | 2016-03-23 | 北京理工大学 | Method for determining distributed explosive source triggering parameters |
| CN105676273A (en) * | 2016-01-19 | 2016-06-15 | 北京理工大学 | Design method for high-energy high-frequency explosive seismic source |
| CN108166544A (en) * | 2018-01-11 | 2018-06-15 | 山东大学 | A kind of test pile working mechanism and technique effect comprehensive detection system and method |
| CN109612356A (en) * | 2018-12-19 | 2019-04-12 | 中国地质大学（武汉） | The acquisition methods of concrete duct dynamic response characteristics are closed on when excavation of foundation pit explosion |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ashford et al. | Blast-induced liquefaction for full-scale foundation testing | |
| Massarsch et al. | Ground vibrations induced by impact pile driving | |
| Amoroso et al. | Blast-induced liquefaction in silty sands for full-scale testing of ground improvement methods: Insights from a multidisciplinary study | |
| Mehrzad et al. | Centrifuge study into the effect of liquefaction extent on permanent settlement and seismic response of shallow foundations | |
| Liu et al. | Dynamic response and failure mode of slopes with horizontal soft and hard interbeddings under frequent microseisms | |
| Weaver et al. | Response of 0.6 m cast-in-steel-shell pile in liquefied soil under lateral loading | |
| Calabrese et al. | Analysis of stresses induced in an old deep tunnel by pile driving from the surface | |
| CN107271637A (en) | A kind of large-scale vibrating liquefaction test system and design method | |
| Jastrzębska et al. | Analysis of the vibration propagation in the subsoil | |
| Finn et al. | Dynamic analyses of an earthfill dam on over-consolidated silt with cyclic strain softening | |
| CN114396082A (en) | Method for testing power characteristics of nuclear power plant pile foundation by adopting underground explosion means | |
| Scott et al. | Full-scale dynamic lateral pile tests | |
| RU2406805C1 (en) | Method to improve seismic reliability of foundations | |
| Gabassi et al. | 3D FEM analysis of soil improving resin injections underneath a mediaeval tower in Italy | |
| Souri | Development of a design guideline for pile foundations subjected to liquefaction-induced lateral spreading | |
| Albano et al. | Performance based seismic analysis of an existing rockfill dam | |
| RU2273035C2 (en) | Method for controlling shifts mode in fragments of seismic-active tectonic fractures | |
| Wang | Research on dynamic response of anchored jointed rock slope under traffic load | |
| Sekiguchi et al. | Evaluation of seismic behaviour of the insulated pile foundation based on site model experiment | |
| Andersen | Performance of a full-scale Rammed Aggregate Pier group in silty sand based on blast-induced liquefaction testing in Emilia-Romagna, Italy | |
| Gohl et al. | Explosive compaction of granular soils and in situ liquefaction testing using sequential detonation of explosives | |
| Seiki et al. | Seismic response of numerical analysis and field measurement in Oya tuff underground quarry | |
| Matsumoto et al. | Trend of research and practice of pile foundations in Japan | |
| Aghayarzadeh | Continuum-based numerical simulation of static and high-strain dynamic pile load testing adopting advanced soil models | |
| Rasheed et al. | Study the Behaviour of the Natural Clay Soil Shallow Foundation System Subjected to Impact Loads |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |