Cast-in-situ bored pile construction risk analysis method and system

Abstract

The invention provides a cast-in-situ bored pile construction risk analysis method and system, and belongs to the technical field of risk identification, and the method comprises the following steps: determining a top event of a cast-in-situ bored pile construction risk by using an accident tree analysis method, analyzing an intermediate event and a basic event of an accident according to the top event, and constructing an accident tree; solving a minimum cut set of top events in the accident tree by using a Boolean algebraic method; drawing a dual tree of the accident tree by using duality of the minimum path set and the minimum cut set, and solving the accident tree by using a Boolean algebraic method to obtain the minimum path set of the top event; judging the structural importance degree of the basic event to the top event according to the occurrence frequency of the basic event in the minimum cut set or the minimum path set; and judging the risk factor of the top event through the minimum cut set, the minimum path set or the structural importance degree. According to the invention, the occurrence of accidents can be comprehensively analyzed, and prevention measures with strong pertinence are provided for avoiding the occurrence of accidents.

Description

Technical Field

[0001] The present invention belongs to the technical field of risk identification, and in particular relates to a bored cast-in-place pile construction risk analysis method and system. Background Art

[0002] Due to their many advantages, bored cast-in-place piles are widely used in building foundations, underground continuous walls for railway and highway bridge piers, and dam foundation treatment. However, the quality of bored cast-in-place piles is difficult to control, and pile breakage is a common occurrence. A broken pile occurs when the concrete becomes discontinuous after solidification, with the center filled with mud or a soft, unsolidified concrete mass with a high water-cement ratio, or a loose mass after solidification. Broadly speaking, while a solidified pile is continuous, if the solid length is shorter than the designed length and the lower end is a soft concrete mass, this also falls under this category. Broken bored cast-in-place piles are serious engineering accidents, significantly reducing the pile's longitudinal and lateral bearing capacity, failing to meet design requirements. They also result in a waste of manpower, material, and financial resources, particularly delaying the construction period.

[0003] In order to overcome the defects of long construction period, waste of materials and increased labor costs, the prior art discloses a one-time pouring construction technology for the static pressure test pile head of bored cast-in-place piles. In the process of detecting the bearing capacity of a single bored cast-in-place pile by static load test, the bored cast-in-place pile is first constructed. After the pile body concrete reaches a certain strength (generally cured for 21 days), the pile head is excavated, and the pile head concrete is chiseled out to dense concrete before installing steel bars, mesh and steel casing. Then, concrete of a higher grade of strength is poured, and finally cured to the design strength. After the pile head concrete meets the requirements, a static load test is performed. This method uses a one-time pouring of the bored cast-in-place pile head to replace the two-time pouring production process in the prior art, which not only shortens the construction period, but also reduces material waste and reduces labor costs. However, there are still risks in the application of this technology. In order to prevent the occurrence of risk accidents, it is very necessary to study the detailed process of accidents caused by safety hazards and propose scientific and efficient preventive measures based on the analysis results. Summary of the Invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a bored cast-in-place pile construction risk analysis method, comprising the following steps:

[0005] The steps include:

[0006] The accident tree analysis method is used to analyze the risks in the bored pile construction process. The potential accidents caused by the risks are regarded as the top events of bored pile construction risks. The intermediate events and basic events of the accidents are analyzed based on the top events. The accident tree is constructed based on the top events, intermediate events and basic events.

[0007] Use Boolean algebra to find the minimum cut set of the top event in the fault tree;

[0008] Draw the dual tree of the fault tree based on the minimum cut set, use Boolean algebra to solve the dual tree, and obtain the minimum path set for the top event to occur;

[0009] The structural importance of basic events to top events is determined by the number of times basic events appear in the minimum cut set or minimum path set;

[0010] The risk factors for the occurrence of the top event are determined by the minimum cut set, the minimum path set or the structural importance.

[0011] Preferably, the accident tree analysis method is used to determine the top event of bored pile construction risk, and the intermediate events and basic events of the accident are analyzed based on the top event, including the following steps:

[0012] Use the accident tree analysis method to identify the risks in the bored pile construction process and determine the accidents that may occur;

[0013] Analyze the causes and consequences of the accident, identify the basic events that led to the accident, and list the causal relationships between the events based on the principles of the accident;

[0014] Determine the direct and potential causes of the accident based on the causal relationship between various events;

[0015] The accident is regarded as the top event, and the direct cause and potential cause of the accident are regarded as the intermediate event and basic event respectively;

[0016] The top events, intermediate events and basic events are connected with logical symbols to obtain a constructed accident tree.

[0017] Preferably, the top event is a bored pile accident T, the intermediate events include serious quality defects in the engineering entity P1, chaotic construction site management P2, failure of the supervision unit to perform supervision duties P3 and problems with the steel cage B1, and the basic events include untimely concrete pouring X1, unqualified bored pile foundation X2, immature technical solution X3, failure to conduct technical briefing X4, unlicensed workers X5, no quality assurance system X6, failure to verify the qualifications of the on-site construction unit X7, failure to stop illegal construction in time X8, failure to conduct reinforcement inspection before lifting the steel cage X9, direct use of wire rope to lift the steel cage X10, inappropriate steel cage size X11 and poor steel cage quality X12.

[0018] Preferably, the logical symbols include "OR gate" and "AND gate".

[0019] Preferably, the steps of using Boolean algebra to solve the minimum cut set of the top event in the fault tree are: starting from the top event, replace the previous level event with the next level event in a certain order, wherein the events connected by "OR gates" are arranged in columns, and the events connected by "AND gates" are arranged in rows, and the replacement is carried out step by step until all are represented by basic events; the calculation formula of the minimum cut set is:

[0020] T=P1P2P3

[0021] =(X1+B1+X2)(X3+X4+X5+X6)(X7+X8)

[0022] =(X1+X9+X 10 +X 11 +X 12 +X2)(X7+X8)(X3+X4+X5+X6)

[0023] =X1X3X7+X1X3X8+X1X4X7+X1X4X8+X1X5X7+X1X5X8+

[0024] X1X6X7+X1X6X8+X2X3X7+X2X3X8+X2X4X7+X2X4X8+

[0025] X2X5X7+X2X5X8+X2X6X7+X2X6X8+X9X3X7+X9X3X8+

[0026] X9X4X7+X9X4X8+X9X5X7+X9X5X8+X9X6X7+X9X6X8+

[0027] X 10 X3X7+X 10 X3X8+X 10 X4X7+X 10 X4X8+X 10 X5X7+X 10 X5X8+

[0028] X 10 X6X7+X 10 X6X8+X 11 X3X7+X 11 X3X8+X 11 X4X7+X 11 X4X8+

[0029] X 11 X5X7+X 11 X5X8+X 11 X6X7+X 11 X6X8+X 12 X3X7+X12 X3X8+

[0030] X 12 X4X7+X 12 X4X8+X 12 X5X7+X 12 X5X8+X 12 X6X7+X 12 X6X8;

[0031] In the formula, T is the top event, which is a bored pile accident; P1 is the existence of serious quality defects in the engineering entity; P2 is the chaotic management of the construction site; P3 is the failure of the supervision unit to perform its supervision duties; B1 is the problem of the steel cage; X1 is the basic event, including the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X4 is the lack of technical briefing; X5 is the unlicensed operation of the operator; X6 is the lack of a quality assurance system; X7 is the failure to verify the qualifications of the on-site construction unit; X8 is the failure to stop the illegal construction in time; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X4 is the failure to conduct technical briefing; X5 is the failure of the operator to work without a license; X6 is the lack of a quality assurance system; X7 is the failure to verify the qualifications of the on-site construction unit; X8 is the failure to stop the illegal construction in time; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the basic event, which includes the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the failure to conduct technical briefing; X1 is the failure to conduct technical briefing; X1 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the failure to 10 To directly use wire rope to lift the steel cage, X 11 The size of the steel cage is not suitable, X 12 The quality of the steel cage is poor.

[0032] Preferably, the minimum cut set for the occurrence of the top event is 48 groups, specifically:

[0033] E1={X1,X3,X7}, E2={X1,X3,X8}, E3={X1,X4,X7}, E4={X1,X4,X8},

[0034] E5={X1,X5,X7}, E6={X1,X5,X8}, E7={X1,X6,X7}, E8={X1,X6,X8},

[0035] E9={X2,X3,X7},E 10 ={X2,X3,X8},E 11 ={X2,X4,X7},E 12 ={X2,X4,X8},

[0036] E 13 ={X2,X5,X7},E 14 ={X2,X5,X8},E 15 ={X2,X6,X7},E 16 ={X2,X6,X8},

[0037] E 17 ={X9,X3,X7},E 18 ={X9,X3,X8},E 19={X9,X4,X7},E 20 ={X9,X4,X8},

[0038] E 21 ={X9,X5,X7},E 22 ={X9,X5,X8},E 23 ={X9,X6,X7},E 24 ={X9,X6,X8},

[0039] E 25 ={X 10 ,X3,X7},E 26 ={X 10 ,X3,X8},E 27 ={X 10 ,X4,X7},E 28 ={X 10 ,X4,X8},

[0040] E 29 ={X 10 ,X5,X7},E 30 ={X 10 ,X5,X8},E 31 ={X 10 ,X6,X7},E 32 ={X 10 ,X6,X8},

[0041] E 33 ={X 11 ,X3,X7},E 34 ={X 11 ,X3,X8},E 35 ={X 11 ,X4,X7},E 36 ={X 11 ,X4,X8},

[0042] E 37 ={X 11 ,X5,X7},E 38 ={X 11 ,X5,X8},E 39 ={X 11 ,X6,X7},E 40 ={X 11 ,X6,X8},

[0043] E 41 ={X 12 ,X3,X7},E 42 ={X 12 ,X3,X8},E 43 ={X12 ,X4,X7},E 44 ={X 12 ,X4,X8},

[0044] E 45 ={X 12 ,X5,X7},E 46 ={X 12 ,X5,X8},E 47 ={X 12 ,X6,X7},E 48 ={X 12 ,X6,X8}.

[0045] Preferably, the calculation formula of the minimum path set is:

[0046] T * =P1 * +P2 * +P3 * =(X1 * B1 * X2 * )+(X3 * X4 * X5 * X6 * )+(X7 * X8 * )

[0047] =(X1 * X9 * X 10 * X 11 * X 12 * X2 * )+(X3 * X4 * X5 * X6 * )+(X7 * X8 * );

[0048] In the formula, in the formula, T * 、P1 * 、P2 * 、P3 * 、B1 * 、X1 * 、X2 * 、X3 * 、X4 * 、X5 * 、X6 * 、X7 * 、X8 *、X9 * 、X 10 * 、X 11 * and X 12 * They are T, P1, P2, P3, B1, X1, X2, X3, X4, X5, X6, X7, X8, X9, X 10 、X 11 and X 12 The dual tree of

[0049] The minimum path sets of the top events obtained are 3 groups, specifically:

[0050] E1 * ={X1 * X9 * , X 10 * X 11 * X2 *}, E2 * ={X3 * X4 * X5 * X6 *}, E3 * ={X7 * X8 *}.

[0051] Preferably, the determination formula of the structural importance is:

[0052]

[0053] Where: I(i) is the basic event X i Judgment value of structural importance; X i ∈K j The basic event Xi belongs to the minimum cut set or minimum path set of Kj; n i For basic event X i The number of basic events contained in the minimum cut set or minimum path set.

[0054] The present invention also provides a bored pile construction risk analysis system, comprising:

[0055] The accident tree construction module is used to analyze the risks in the bored pile construction process using the accident tree analysis method. The potential accidents caused by the risks are regarded as the top events of bored pile construction risks. The intermediate events and basic events of the accidents are analyzed based on the top events. The accident tree is constructed based on the top events, intermediate events and basic events.

[0056] Minimum cut set acquisition module, used to solve the minimum cut set of the top event in the fault tree using Boolean algebra method;

[0057] The minimum path set acquisition module is used to draw the dual tree of the fault tree by utilizing the duality of the minimum path set and the minimum cut set, and solve the fault tree using Boolean algebra to obtain the minimum path set for the occurrence of the top event;

[0058] A structural importance acquisition module is used to determine the structural importance of basic events to top events based on the number of times the basic events appear in the minimum cut set or the minimum path set;

[0059] The risk determination module is used to determine the risk factors of the top event through the minimum cut set, minimum path set or structural importance.

[0060] The bored cast-in-place pile construction risk analysis method provided by the present invention has the following beneficial effects:

[0061] The present invention adopts the fault tree analysis method to analyze the intermediate events and basic events that lead to the occurrence of bored pile accidents of top events, and constructs an fault tree; by solving the fault tree, the minimum cut set and minimum diameter set of the top event can be solved; the structural importance of the top event can be determined by the minimum cut set and minimum diameter set; the risk factors of the top event are determined by the structural importance, so as to provide targeted preventive measures to avoid the occurrence of accidents;

[0062] The risk analysis method of the present invention calculates that there are 48 minimum cut sets and 3 minimum diameter sets that lead to pile breakage accidents, which indicates that there are 48 possibilities leading to bored cast-in-place pile breakage accidents. Therefore, bored cast-in-place pile breakage accidents are relatively easy to occur. However, as long as any one of the three minimum diameter sets can be selected for targeted prevention, accidents can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] To more clearly illustrate the embodiments of the present invention and its design, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0064] Figure 1 An accident tree diagram of an embodiment of the present invention;

[0065] Figure 2 A success tree diagram of an embodiment of the present invention;

[0066] Figure 3 are AND gate symbols and OR gate symbols;

[0067] Figure 4It is the accident tree structure diagram;

[0068] Figure 5 is the minimum path set structure diagram;

[0069] Figure 6 It is a ranging system for underwater acoustic sensors;

[0070] Figure 7 It is a three-dimensional coordinate measurement system for hole wall;

[0071] Figure 8 It is a pile hole measurement system. DETAILED DESCRIPTION

[0072] In order to enable those skilled in the art to better understand the technical solution of the present invention and to be able to implement it, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0073] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0074] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0075] Example

[0076] The present invention provides a bored pile construction risk analysis method and system, the method comprising the following steps:

[0077] Step 1: Use the accident tree analysis method to analyze the risks in the bored pile construction process, and take the potential accidents caused by the risks as the top events of bored pile construction risks. According to the top events, analyze the intermediate events and basic events of the accidents; and construct an accident tree based on the top events, intermediate events and basic events.

[0078] Accident tree theory, also known as fault tree analysis, is a key method for risk analysis of specific projects, particularly those involving bored pile construction. This method identifies risks associated with bored pile construction and logically maps the causal relationships between events that could lead to an accident. This analysis then identifies the direct causes of the accident and further reveals potential causes of bored pile construction accidents.

[0079] The accident tree theory is an analytical method that uses graphics to represent the reasoning process. It generally begins with the final outcome of an accident and conducts a layered, in-depth analysis around a specific incident. The accident tree graphically expresses the inherent connections between events within the accident system and identifies the logical relationship between unit failures and system accidents, facilitating the identification of system weaknesses. It boasts clear thinking and strong logic. When constructing an accident tree, one should first determine the potential causes of the accident in the system, clarify the cause and effect of the accident, identify the basic events that may have caused the accident, and then, based on the principles of the accident, list the causal relationships between each event and connect them with logical symbols to complete the construction of the accident tree. As a graphical deductive reasoning method, the accident tree analysis method consists of graphic symbols with specific meanings. Symbols of different shapes represent different meanings. Commonly used graphic symbols include event symbols and logic gate symbols.

[0080] The most commonly used symbol in the accident tree is the event symbol, which has two main forms: Figure 2 The following are represented by rectangles and circles. Rectangles represent non-bottom-level events that require further analysis, including top events and intermediate events; circles represent basic events that cannot be further subdivided, usually connecting top events and intermediate events.

[0081] Logic gate symbols mainly include AND gate symbols and OR gate symbols, such as Figure 3 As shown in the figure, the AND gate symbol indicates that the event occurs when all input events occur; the OR gate symbol indicates that the event occurs when any one or more input events occur.

[0082] In the present invention, the basic process of fault tree analysis is as follows:

[0083] The present invention analyzes the mechanism of bored pile breakage accidents (top events) from the perspectives of people, machines, materials, methods, and environment, and finds out that the main factors (intermediate events) leading to the accidents are: serious quality defects in the engineering entity, chaotic construction site management, and the supervision unit's failure to perform its supervisory duties. There are 12 basic events that lead to top events, specifically, untimely concrete pouring, unqualified bored pile foundations, immature technical solutions, lack of technical briefing, unlicensed workers, lack of a quality assurance system, failure to verify the qualifications of on-site construction units, failure to promptly stop illegal construction, failure to conduct reinforcement inspections before lifting the steel cage, direct use of wire ropes to lift the steel cage, inappropriate steel cage size, and poor steel cage quality.

[0084] Construct an accident tree based on top events, intermediate events and basic events, as follows: Figure 4 As shown, Figure 4 The meanings of the symbols are shown in Table 1.

[0085] Table 1 The meaning of each symbol in the accident tree

[0086]

[0087]

[0088] Step 2: Use Boolean algebra to find the minimum cut set of the top event in the fault tree. Common Boolean algebra operation rules are shown in Table 2:

[0089] Table 2 can be simplified to obtain the following simplest disjunctive standard formula:

[0090]

[0091]

[0092] Table 2 Boolean algebra operation rules

[0093]

[0094] Define the sum of Boolean terms in disjunctive normal form A i There is no inclusion relationship between the items in it, that is, the Boolean product of any basic event is not included in the Boolean product of other basic events, then the disjunctive standard form is the simplest disjunctive standard form, then A i is the cut set of the structure function f. Define the product B of the Boolean terms of the disjunctive normal form i There is no inclusion relationship between the items in the formula, that is, the Boolean sum of any basic event is not included in the Boolean sum of other basic events, then the disjunctive standard form is the simplest disjunctive standard form, then B i is the radius set of the structure function f.

[0095] If all the basic events of the fault tree occur, the top event will definitely occur. The set of basic events with the minimum number of events that lead to the occurrence of the top event is called the minimum cut set. Each minimum cut set represents a situation in which the top event occurs. By solving the minimum cut set T, the danger of the system can be qualitatively analyzed.

[0096] To calculate the minimum cut set, start with the top event and replace the previous one with the next-level event in a certain order. Events connected by OR gates are arranged in columns, and events connected by AND gates are arranged in rows. This replacement continues until all events are represented by basic events. The final set of basic events in each row is the cut set. Further simplification until there are no containment relationships between the sets is the minimum cut set.

[0097] The set of basic events in the fault tree that prevents the top event from occurring is called the path set, and the set of the minimum number of basic events that prevents the top event from occurring is called the minimum path set. The minimum path set represents the safety of the system. First, find the minimum cut set of the dual tree, and then interchange the "AND gate" and "OR gate" to obtain the minimum path set T'.

[0098] In general, not all basic events will occur simultaneously. The top event can only occur when certain basic events occur. The set of basic events that can lead to the top event is called a cut set. The minimum set of basic events that can lead to the top event is called a minimum cut set. The minimum cut set is obtained using Boolean algebra as follows:

[0099] T=P1P2P3

[0100] =(X1+B1+X2)(X3+X4+X5+X6)(X7+X8)

[0101] =(X1+X9+X 10 +X 11 +X 12 +X2)(X7+X8)(X3+X4+X5+X6)

[0102] =X1X3X7+X1X3X8+X1X4X7+X1X4X8+X1X5X7+X1X5X8+

[0103] X1X6X7+X1X6X8+X2X3X7+X2X3X8+X2X4X7+X2X4X8+

[0104] X2X5X7+X2X5X8+X2X6X7+X2X6X8+X9X3X7+X9X3X8+

[0105] X9X4X7+X9X4X8+X9X5X7+X9X5X8+X9X6X7+X9X6X8+

[0106] X 10 X3X7+X 10 X3X8+X 10 X4X7+X 10 X4X8+X 10 X5X7+X 10 X5X8+

[0107] X 10 X6X7+X 10 X6X8+X 11 X3X7+X 11 X3X8+X 11 X4X7+X 11 X4X8+

[0108] X 11 X5X7+X 11 X5X8+X 11 X6X7+X 11 X6X8+X 12 X3X7+X 12 X3X8+

[0109] X 12 X4X7+X 12 X4X8+X 12 X5X7+X 12 X5X8+X 12 X6X7+X 12 X6X8

[0110] From this calculation, we can get that the top-level event T has at most 48 minimum cut sets, as follows:

[0111] E1={X1,X3,X7}, E2={X1,X3,X8}, E3={X1,X4,X7}, E4={X1,X4,X8},

[0112] E5={X1,X5,X7}, E6={X1,X5,X8}, E7={X1,X6,X7}, E8={X1,X6,X8},

[0113] E9={X2,X3,X7},E 10 ={X2,X3,X8},E 11 ={X2,X4,X7},E 12 ={X2,X4,X8},

[0114] E 13 ={X2,X5,X7},E 14 ={X2,X5,X8},E 15 ={X2,X6,X7},E 16={X2,X6,X8},

[0115] E 17 ={X9,X3,X7},E 18 ={X9,X3,X8},E 19 ={X9,X4,X7},E 20 ={X9,X4,X8},

[0116] E 21 ={X9,X5,X7},E 22 ={X9,X5,X8},E 23 ={X9,X6,X7},E 24 ={X9,X6,X8},

[0117] E 25 ={X 10 ,X3,X7},E 26 ={X 10 ,X3,X8},E 27 ={X 10 ,X4,X7},E 28 ={X 10 ,X4,X8},

[0118] E 29 ={X 10 ,X5,X7},E 30 ={X 10 ,X5,X8},E 31 ={X 10 ,X6,X7},E 32 ={X 10 ,X6,X8},

[0119] E 33 ={X 11 ,X3,X7},E 34 ={X 11 ,X3,X8},E 35 ={X 11 ,X4,X7},E 36 ={X 11 ,X4,X8},

[0120] E 37 ={X 11 ,X5,X7},E 38 ={X 11 ,X5,X8},E 39 ={X 11 ,X6,X7},E 40 ={X 11 ,X6,X8},

[0121] E 41 ={X 12 ,X3,X7},E 42 ={X 12 ,X3,X8},E 43 ={X 12 ,X4,X7},E 44 ={X 12 ,X4,X8},

[0122] E 45 ={X 12 ,X5,X7},E 46 ={X 12 ,X5,X8},E 47 ={X 12 ,X6,X7},E 48 ={X 12 ,X6,X8}.

[0123] Step 3: Using the duality of the minimum path set and the minimum cut set, draw the dual tree of the fault tree, use Boolean algebra to solve the fault tree, and obtain the minimum path set for the occurrence of the top event.

[0124] Using the duality of the minimum path set and the minimum cut set, draw the dual tree of the fault tree, that is, the success tree, and find the minimum cut set of the success tree, which is the minimum path set of the original fault tree. Figure 5 As shown:

[0125] Find the minimum cut set of the success tree. The minimum cut set is the minimum path set of the original fault tree. Using Boolean algebra, we can get:

[0126] T * =P1 * +P2 * +P3 * =(X1 * B1 * X2 * )+(X3 * X4 * X5 * X6 * )+(X7 * X8 * )

[0127] =(X1 * X9 * X 10 * X 11 * X 12 * X2 * )+(X3 * X4* X5 * X6 * )+(X7 * X8 * );

[0128] Therefore, the minimum cut set of the success tree is 3 groups, and the minimum path set of the original accident tree is also these 3 groups.

[0129] Right now:

[0130] E1 * ={X1 * X9 * , X 10 * X 11 * X2 *}, E2 * ={X3 * X4 * X5 * X6 *}, E3 * ={X7 * X8 *};

[0131] Step 4: Determine the structural importance of the basic event to the top event based on the number of times the basic event appears in the minimum cut set or minimum path set.

[0132] By analyzing the importance of each basic event in the fault tree based on the degree of influence of each basic event on the top event, we can derive the importance ranking of each basic event, thereby identifying relatively important basic events and strictly controlling them. Here, I(i) represents the structural importance coefficient of the basic event Xi. If they appear few times in the minimum cut set of few events, but appear many times in the minimum cut set of many events, or in other more complex situations, the following approximate discriminant can be used for calculation:

[0133]

[0134] Where: I(i) is the basic event X i Approximate judgment value of structural importance; X i ∈K j For basic event X i Belongs to K j Minimum cut set or minimum path set; n i For basic event X i The number of basic events contained in the minimum cut set or minimum path set.

[0135] The structural importance coefficient of each basic event on the formwork support collapse accident is:

[0136]

[0137]

[0138]

[0139] Therefore, the order of importance of each basic event is:

[0140] I (7) =I (8) >I (3) =I (4) =I (5) =I (6) >I (1) =I (2) =I (9) =I (10) =I (11) =I (12) ;

[0141] Step 5: Determine the risk factors of the top event through the minimum cut set, minimum path set or structural importance.

[0142] (1) It can be seen from the accident tree that the number of "OR" gates is large (accounting for 80%), and the number of "AND" gates is small (accounting for 20%), which indicates that the danger of this system (casting failure engineering accident) is relatively large.

[0143] (2) From the perspective of the minimum cut set, any minimum cut set is a "possible channel" for the occurrence of the top event of the event. The more minimum cut sets there are in the fault tree, the more likely the top event is to occur, and the more dangerous the system is. There are 48 minimum cut sets in this fault tree, indicating that there are 48 "possible channels" leading to the occurrence of bored pile breakage accidents. This fully reflects the high possibility and danger of pile breakage accidents, and the difficulty of prevention. If we take any minimum cut set E2 = {X1, X3, X8} for analysis, only the three basic events X1 (untimely concrete pouring), X3 (immature technical solution), and X8 (supervisor failed to stop illegal construction in time) occur simultaneously to cause the pouring failure accident.

[0144] (3) From the perspective of the minimum path set, the accident tree has a minimum path set, and there is a possibility that the top event will not occur. The more minimum path sets there are, the more ways the top event will not occur, and the safer the system will be. The use of the minimum path set can select the best solution to ensure system safety and provide an effective basis for preventing and controlling accidents. In the accident tree of the broken pile project, there are 48 minimum cut sets and 3 minimum path sets, so it is more convenient to use the minimum path set analysis. E2*={X3*X4*X5*X6*} indicates that if X3*, X4*, X5*, X6* do not occur, the top event will not occur. In other words, if the construction unit strengthens on-site management before the construction of the project, strictly equips corresponding quality management personnel in accordance with the established quality assurance system, and conducts technical briefings for on-site workers in advance according to the construction technical plan, the occurrence of construction accidents can be avoided.

[0145] (4) From the perspective of structural importance, the probability of occurrence of basic events is not considered, and only the degree of influence of the occurrence of each basic event on the occurrence of the top event is analyzed from the structure of the accident tree. The accident tree is composed of many basic events, which have an impact on the top event, but the degree of influence is different. When formulating safety precautions, there must be a sequence and priority so that the system can achieve the goals of economy, effectiveness and safety. For example, for the basic events of this accident, X7 (failure to verify the qualifications of the on-site construction unit) and X8 (failure to stop illegal construction in time) have the greatest structural importance, indicating that they occupy the primary position in the system, followed by X3 (immature technical plan), X4 (failure to conduct technical briefing), X5 (operators working without a license), X6 (no quality assurance system), and finally X1 (untimely concrete pouring), X9 (failure to conduct reinforcement inspection before lifting the steel cage), X10 (failure to conduct technical briefing before lifting the steel cage), X11 (failure to conduct technical briefing before lifting the steel cage), X12 (failure to conduct technical briefing before lifting the steel cage), X13 (failure to conduct technical briefing before lifting the steel cage), X14 (failure to conduct technical briefing before lifting the steel cage), X15 (failure to conduct technical briefing before lifting the steel cage), X16 (failure to conduct technical briefing before lifting the steel cage), X17 (failure to conduct technical briefing before lifting the steel cage), X18 (failure to conduct technical briefing before lifting the steel cage), X19 (failure to conduct technical briefing before lifting the steel cage), X11 (failure to conduct technical briefing before lifting the steel cage), X11 (failure to conduct technical briefing before lifting the steel cage), X12 (failure to conduct technical briefing before lifting the steel cage), X13 (failure to conduct technical briefing before lifting the steel cage), X14 (failure to conduct technical briefing before lifting the steel cage), X15 (f 10 (Use steel rope to lift steel cage directly), X 11 (Rebar cage size is not suitable), X 12 (poor quality of steel cage), X2 (unqualified cast-in-place pile foundation). From this, we can see that when formulating accident prevention measures, we should proceed from reality and select the most effective preventive measures according to the order of importance of the incident, from the largest to the smallest.

[0146] From the above analysis, we can know that there are 48 minimum cut sets and 3 minimum diameter sets of pile breakage accidents that may be caused by the new bored cast-in-place pile casting technology. This shows that there are 48 possibilities that may lead to bored cast-in-place pile breakage accidents. Therefore, bored cast-in-place pile breakage accidents are relatively easy to occur in construction, but as long as targeted preventive measures can be taken by taking any of the 3 groups of minimum diameter sets, such accidents can be avoided. It can be seen that the use of the accident tree analysis method to analyze possible accidents can not only make a systematic explanation of the logical relationship between the various factors that lead to the accident and understand the key points of the accident tree, but also broaden the thinking of safety management personnel, make a comprehensive analysis of the occurrence of accidents, and provide targeted preventive measures to avoid the occurrence of accidents. The preventive measures recommended by the present invention are as follows:

[0147] (1) The main human factors in pile breakage accidents include technicians, supervisors, and workers who are irresponsible for their work or have low personal qualities. First, we must strengthen the education of technicians, so that their professional level can be continuously improved, and workers without a license should be prohibited from working. We must strengthen training for workers, carry out relevant knowledge learning with safety and quality as the theme, and carry out various forms of competition activities, so that wages are not only linked to the amount of work, but more importantly, to the quality of work, so that the quality of work is the main thing while taking quantity into consideration. Secondly, when carrying out their work, leaders should try their best to be people-oriented, strengthen the sense of responsibility of technicians and workers, especially technicians, and give technicians certain powers so that they can take the initiative in their work. At the same time, we should increase the intensity of assessment, make rewards and punishments clear, and maximize the work enthusiasm of employees. Finally, during the construction process, we must respect the supervisor and cooperate with the supervisor's work as much as possible. Only in this way can we improve the quality of cast-in-place piles and increase the reliability of the project.

[0148] (2) For physical factors, such as equipment failure and inaccurate measuring tools, the reliability of the system can be improved by using component redundancy according to system reliability theory, such as using spare mechanical equipment and two measuring tools. This will increase construction costs, but on balance, these additional expenses can be compensated by the improvement of system reliability.

[0149] (3) Strengthen daily production management, especially technical management, to prevent problems from happening. For example, before pouring concrete, all preparations for pouring concrete (equipment, materials, personnel, etc.) and emergency measures (temporary treatment of pipe jams, pipe breaks, water outages, and personal injuries) should be completed to ensure the continuity and smoothness of concrete pouring and to avoid work stoppages during the pouring process. The concrete used for pouring should be strictly prepared in accordance with the design requirements of the concrete strength grade and relevant regulations and specifications. After the pile hole is drilled, the hole must be cleaned carefully, and the thickness of the sediment at the bottom of the hole must be checked strictly in accordance with relevant regulations and specifications. Before pouring, the funnel and conduit should be rinsed with clean water, and the upper and lower outlets of the conduit should be checked to see if the disc or threaded connection of the conduit is sealed and unobstructed.

[0150] (4) Adhere to the necessary management system. Personnel must be familiar with the working face operation procedures and the technical operation procedures of each type of work, and can only take up their posts after passing the examination. Strictly implement the system of knocking on the roof and asking about the top. If loose stones are found in the roof or coal seam, they must be dealt with before work can begin. Strengthen the acceptance system. Each shift on the working face should have a full-time acceptance inspector to inspect the specifications and quality of each section of support from the head to the tail of the machine. If unqualified products are found, they should be reworked in time. Adhere to the post responsibility system, with each section responsible from the head to the tail of the machine. The pillars should be numbered and the responsibilities should be assigned to individuals. If leaking pillars or broken hinged roof beams are found during the shift, they should be promptly recovered to the designated location and it is strictly forbidden to continue using them. Strictly implement the handover system, and hand over to people according to the type of work on site. New situations must be thoroughly understood. Strictly implement the roof management analysis system. During the initial pressure and periodic pressure of the working face, a roof management leadership group should be established and roof management analysis meetings should be held regularly to summarize the good experience of roof management, point out the problems on site, implement responsibilities, formulate measures, and constantly master the laws of roof management.

[0151] The present invention also provides a bored pile construction risk analysis system, comprising:

[0152] The accident tree construction module is used to analyze the risks in the bored pile construction process using the accident tree analysis method. The potential accidents caused by the risks are regarded as the top events of bored pile construction risks. The intermediate events and basic events of the accidents are analyzed based on the top events. The accident tree is constructed based on the top events, intermediate events and basic events.

[0153] Minimum cut set acquisition module, used to solve the minimum cut set of the top event in the fault tree using Boolean algebra method;

[0154] The minimum path set acquisition module is used to draw the dual tree of the fault tree by utilizing the duality of the minimum path set and the minimum cut set, and solve the fault tree using Boolean algebra to obtain the minimum path set for the occurrence of the top event;

[0155] A structural importance acquisition module is used to determine the structural importance of basic events to top events based on the number of times the basic events appear in the minimum cut set or the minimum path set;

[0156] The risk determination module is used to determine the risk factors of the top event through the minimum cut set, minimum path set or structural importance.

[0157] Example 2

[0158] Construction steps of the new bored pile pouring technology:

[0159] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to propose a one-time pouring construction method for the static pressure test pile head of bored cast-in-place piles, which adopts the one-time pouring of bored cast-in-place pile heads to replace the two-time pouring production process in the prior art, thereby shortening the construction period, reducing material waste, and reducing labor costs. The one-time pouring construction method for the static pressure test pile head of bored cast-in-place piles provided by the present invention comprises the following steps: S1, installing a borehole steel casing in the bored cast-in-place pile hole that has been drilled to prevent the rock and soil around the bored pile hole wall from falling into the bored cast-in-place pile hole and protecting the hole wall; S2, designing the size of the steel cage according to the length of the bored cast-in-place pile to ensure that the top surface of the steel cage is 50 cm above the ground; S3, after the bored cast-in-place pile hole in step S1 is accepted, installing the designed and manufactured steel cage in the bored cast-in-place pile hole; S4, adding the bored cast-in-place pile to the bored cast-in-place pile hole. Pour concrete into the hole, and clean up the scum after the concrete is poured and flush with the ground; S5, install the pile head steel casing on the ground, and then pull out the hole steel casing; S6, continue pouring concrete and vibrate it to make it dense until it reaches the top of the pile head steel casing; S7, smooth the pile head with slurry, and maintain the bored pile; S8, after the maintenance period, use static load test equipment to conduct static load test on the bored pile to detect the bearing capacity of a single bored pile. A jack is set at the bottom of the static load test equipment, and the static load test equipment detects the bearing capacity of a single bored pile through the mechanical balance principle of the jack.

[0160] Application analysis of bored pile casting technology:

[0161] Construction preparation analysis:

[0162] (1) Before the construction of bored piles, the construction materials have been processed to ensure that materials such as cement, concrete and steel bars meet the standards of my country's building materials.

[0163] (2) Prepare a special construction plan based on the geological conditions and climate conditions of the construction site, and carry out technical briefings to ensure that operators have a full understanding of the use of equipment and specific operating techniques. During the construction process, appropriate protective measures need to be taken to ensure that no safety accidents occur.

[0164] Buried casing analysis:

[0165] The burial of casing has a great influence on the verticality of the bored pile body and the quality of its formation. When burying the casing, it should be ensured that the excavated foundation pit is 200mm larger than the designed pile diameter. In order to ensure the quality of the excavation, it is recommended to use manual excavation during excavation, and the depth is generally 1.10-1.30m. When excavating to the stable soil layer, the steel casing should be installed in time. When installing the steel casing, it should be ensured that the center line of the steel casing is completely consistent with the center line of the pile position. At the same time, reliable measures should be taken to reinforce the casing to ensure that the installation position of the steel casing is accurate and stable; again, the acceptance indicators such as the casing center deviation and inclination should meet the requirements of the specifications. After acceptance by the on-site engineer, the gap between the casing and the pit wall should be backfilled with plain fill.

[0166] Equipped with mud analysis

[0167] Mud serves as a wall protector and lubricant, and is essential for ensuring the quality of bored concrete pile construction. Especially during construction involving thick layers of plain or sandy soil, particular attention should be paid to the quality of the mud. Mud preparation requires the installation of a mud pit at a selected location, using bentonite or silty clay, and mixing the mud to a specific density based on geological conditions. During bored pile construction, technicians must continuously adjust the mud mix according to changing geological conditions, selecting the most appropriate ratio. This process requires ensuring not only the quality of the mud but also its overall safety. During construction, constant attention should be paid to the proper operation of the mud recycling system.

[0168] Drilling construction analysis:

[0169] Once the drill rig is properly positioned, drilling can begin. Maintain a minimum penetration of approximately 100 cm per drill. Initially, slow the drilling speed and maintain a steady bucket lowering and slow bucket raising. This is especially true during the 4-6 m section of the borehole. The operator should monitor verticality using the control panel and promptly correct any deviations. The operator should constantly monitor the drill rod for verticality and use the depth counter to control the drilling depth. During the drilling process, slurry should be injected as needed to protect the borehole wall, adjusting the slurry density appropriately. Drilling should be continuous and uninterrupted to prevent collapse. During drilling, construction records should be promptly filled in based on actual site conditions. Slag samples should be collected at locations of soil changes to identify the soil layers for comparison with the geological profiles in the geological survey report. Once the designed rock face is reached, samples should be taken for identification. The hole should be cleaned immediately after the bored pile reaches the desired depth. Pumping and reverse circulation can be used to remove slag until all test indicators of the bottom hole slurry meet design and specification requirements. To ensure the molding quality of bored piles, before pouring concrete, it is necessary to check whether the various indicators and performance of the mud at the bottom of the hole meet the requirements of the specifications. If not, continue to clean the hole until it meets the design requirements. At the same time, check the depth of the hole to determine whether there is any collapse of the hole wall. If so, use a rotary drilling rig to re-drill to the design depth before cleaning the hole.

[0170] Installation of steel cage:

[0171] While the pile is being drilled, the steel cage should be fabricated simultaneously. The drilling rig should be used to move the steel cage in sections above the hole opening. The cage should be extended and inserted into the hole through mechanical connection or welding. Ensure that the reserved length of the pile foundation steel bars meets the requirements. At the same time, the steel cage should meet the following conditions before being hoisted:

[0172] (1) Steel bars that have passed on-site inspection should be stacked according to their specifications and models and marked;

[0173] (2) Before making the steel cage, the steel bars should be cleaned;

[0174] (3) Check the weld appearance quality for defects such as uniformity of molten metal, penetration depth, and weld quality at the steel bar welds;

[0175] (4) The steel cage should be hoisted slowly and aligned with the hole to avoid collision with the hole wall. Do not force it down. If the hoisting is blocked, stop hoisting and find the cause. Do not apply pressure to force it down to avoid collapse of the hole or deformation of the steel cage.

[0176] (5) During the installation process of the qualified steel cage, in order to effectively reduce the deformation of the steel cage and ensure its verticality, a lifting rod should be added at the lifting point to strengthen the stability of the steel cage. At the same time, the connection quality of the steel cage should be inspected section by section, and unqualified steel connection points should be corrected immediately.

[0177] In this embodiment, the completion of bored pile construction is monitored by a monitoring system, which can obtain real-time progress information on pile hole construction. By interacting with the pile hole quality monitoring system, the system can determine key construction nodes such as the current drilling depth of each pile hole and whether concrete pouring is complete. On the monitoring interface, the construction progress can be identified through image processing technology, and the progress percentage can be calculated based on different key construction nodes. For example, the percentage of pile hole drilling progress can be displayed through a progress bar, and completed pile holes can be identified with specific colors or icons. In this way, managers can fully understand the progress of pile hole construction for the entire project without having to visit the site, promptly identify pile holes that are lagging behind, and take appropriate measures to accelerate the construction progress, ensuring the smooth implementation of the overall project construction plan.

[0178] Historical Data Query and Analysis: The system stores and manages historical data on pile hole completion, allowing managers to query and analyze it at any time. Based on criteria such as the pile hole number and construction time, managers can query detailed construction records for specific pile holes, including changes in various quality indicators and construction timelines. By analyzing historical data, construction experience can be summarized and patterns and problems identified during the construction process can be identified.

[0179] The bored pile construction completion monitoring system specifically includes:

[0180] (1) Pile hole quality monitoring system perception layer equipment.

[0181] (1) Underwater acoustic sensor.

[0182] Technical parameters: (frequency range 50-300kHz).

[0183] Function: Moves an ultrasonic transducer vertically along the pile hole, transmitting and receiving acoustic signals to measure cross-sectional data at different heights. This provides raw data for 3D image reconstruction, cavity collapse location and shape analysis, pile hole verticality determination, and overflow coefficient calculation.

[0184] (2) GNSS / Beidou dual-mode positioning module.

[0185] Technical parameters: Supports L1 / L5 band dual-frequency GNSS signal reception and RTK centimeter-level positioning (error <10cm).

[0186] Function: Built-in UWB ultra-wideband chip (±10cm accuracy) provides auxiliary positioning in areas with weak GNSS signals (such as indoors or in urban canyons).

[0187] (3) Internet of Things gateway.

[0188] Technical parameters: Modbus RTU protocol converted to MQTT / TCP.

[0189] Function: Converts the Modbus RTU protocol output by the sensor to MQTT / TCP to enable communication with the cloud platform. Runs lightweight filtering algorithms (such as Kalman filtering) to eliminate noise interference.

[0190] (2) Key equipment at the network layer.

[0191] (1) 5G private network equipment.

[0192] Device model: Huawei 5GAAU (Active Antenna Unit).

[0193] Technical parameters:

[0194] Frequency band support: 3.3GHz-4.9GHz (n78 / n79 bands).

[0195] Transmit power: 24dBm.

[0196] Beamforming: 64T64R antenna array.

[0197] Core network slicing: supports end-to-end latency of ff5ms.

[0198] Function: Provides ultra-low-latency wireless transmission channels (latency <5ms), ensuring real-time interaction between 3D point cloud data and real-time positioning signals. Core network slicing technology allocates independent logical channels to quality monitoring and dispatch systems, prioritizing bandwidth for critical tasks (such as collapse warning).

[0199] (2)Edge computing nodes.

[0200] Device model: NVIDIA Jetson AGX Xavier.

[0201] Technical parameters:

[0202] GPU computing power: 32TOPS (INT8 precision).

[0203] CPU: 6-core ARM Cortex-A76 @ 2.3GHz.

[0204] Memory: 32GB LPDDR5.

[0205] Interface: 4×USB3.2 Gen2, 1×PCIe 16x.

[0206] Function: Run localized 3D reconstruction algorithms (such as voxel cloud denoising) to reduce cloud computing load. Process LiDAR scan data in real time to generate a 3D environmental map of the construction site.

[0207] (3) Data transmission equipment.

[0208] Device model: InfiniBand switch (Mellanox ConnectX-6).

[0209] Technical parameters:

[0210] Bandwidth: 900GB / s (bidirectional).

[0211] Latency: <1ffs.

[0212] Redundancy mechanism: 4x25G port redundancy.

[0213] Function: Enables high-speed data transmission between edge nodes and cloud servers, supporting real-time synchronization of large-scale point cloud data.

[0214] (3) Platform layer.

[0215] The system's platform layer can be summarized as a comprehensive management platform that integrates data processing, analysis, monitoring, and scheduling functions. This platform layer is responsible for the entire pile hole quality monitoring, coordinating and managing various subsystems to ensure accurate data transmission, efficient processing, and intelligent decision-making. The following are the main components and functions of the system platform layer:

[0216] (1) Data collection and processing platform.

[0217] Sensor data reception: responsible for receiving real-time data from various sensors such as underwater acoustic sensors, GPS / Beidou positioning systems, etc.

[0218] Data preprocessing: Perform cleaning, denoising, calibration and other preprocessing operations on the received raw data to ensure the accuracy and reliability of the data.

[0219] Data storage: The processed data is stored in the database for subsequent query and analysis.

[0220] (2) Pile driver monitoring and dispatching platform.

[0221] Real-time location monitoring: The location of the pile driver is monitored in real time through the GPS / Beidou positioning system.

[0222] Construction progress feedback: Get real-time pile hole construction progress information and display it intuitively on the monitoring interface.

[0223] Historical data query and analysis: Store and manage historical data on pile hole completion for easy query and analysis.

[0224] (3) User interface and interactive platform.

[0225] Monitoring interface: Provides an intuitive monitoring interface that displays real-time data on pile hole quality monitoring and pile driver monitoring and scheduling.

[0226] Operation interface: allows managers to perform system settings, data query and other operations.

[0227] Alarm and notification: When an abnormal situation occurs, an alarm signal will be issued in time and relevant personnel will be notified to handle it.

[0228] (4) System integration and interface platform.

[0229] System integration: Integrate various subsystems to ensure smooth data transmission and system collaboration.

[0230] Interface management: Provide interfaces with other systems (such as construction management system, quality management system, etc.) to achieve data sharing and interaction.

[0231] (4) User layer.

[0232] (1)Administrator users.

[0233] Access to the monitoring and scheduling interface: Managers can access the monitoring interface for pile hole quality monitoring through the user layer, view the pile foundation construction results in real time, and fully understand the dynamics and construction status of the pile driver.

[0234] Construction progress management and feedback: At the user level, managers can intuitively see the construction progress of the pile holes. Based on the progress information, they can promptly identify construction risks and take corresponding measures to prevent risks.

[0235] Historical data query and analysis: Managers can query historical data through the user layer, including changes in various quality indicators during the construction process, construction time nodes, and other information. They can analyze this data, summarize construction experience, and identify patterns and problems in the construction process.

[0236] (2) Pile driver operator user.

[0237] Real-time location viewing: Pile driver operators can view the location and movement trajectory of the pile driver they operate through the user layer to understand their own construction status.

[0238] (3) System maintenance personnel users.

[0239] System Configuration and Maintenance: System maintenance personnel configure, maintain, and manage the system through the user layer to ensure normal operation and functional stability. They can access the system's backend management interface to perform operations such as system settings, data backup, and troubleshooting.

[0240] In this embodiment, the completion status of bored pile construction is also displayed through the monitoring system, as follows:

[0241] 1. Underwater acoustic sensors and three-dimensional imaging technology.

[0242] (1) Underwater acoustic sensor measurement technology.

[0243] The core of underwater acoustic sensor ranging is to use the propagation speed of sound waves in water and the time difference to calculate the target distance. The specific formula is: distance d = (sound speed × time difference Δt) / 2. Among them, the speed of sound in water is affected by factors such as temperature, salinity, and pressure, and is generally about 1480-1540m / s. The time difference Δt is the total time from the emission to the reception of the sound wave, including the time of the round-trip path. The system composition of measuring the three-dimensional coordinate data of the hole wall is as follows Figure 6 shown.

[0244] Core components:

[0245] Piezoelectric transducer: responsible for converting electrical signals into sound waves (transmitting) and converting sound waves into electrical signals (receiving).

[0246] Signal conditioning circuit: includes low-noise amplifier (LNA), filter (bandpass filter) and impedance matching circuit to improve signal quality.

[0247] High-precision timing module: uses TDC (Time-to-Digital Converter) or PLL phase-locked loop to achieve nanosecond time measurement to ensure ranging accuracy.

[0248] Microcontroller: such as STM32, FPGA, etc., responsible for controlling the transmission signal and processing the measurement results.

[0249] Key circuit design:

[0250] Transmitter circuit: Uses PWM signal to drive the piezoelectric transducer and controls the transmit power by adjusting the duty cycle.

[0251] Receiver circuit: includes an LNA amplifier to improve the signal-to-noise ratio, a bandpass filter to filter out noise, and a TDC chip to achieve a time measurement circuit with picosecond time resolution.

[0252] Synchronous clock: ensures that the time base of the transmitted and received signals is consistent, improving the ranging accuracy.

[0253] Computer implementation solution:

[0254] Signal transmission: The microcontroller triggers the piezoelectric transducer to emit sound waves through GPIO.

[0255] Waiting for echo: Enter low power mode and wait for the signal to trigger an interrupt.

[0256] Time capture: Use high-precision timing modules to record the timestamps of transmission and reception.

[0257] Data processing: including filtering to eliminate noise and threshold detection of echo signal strength.

[0258] Doppler correction: If the target moves, the speed of sound needs to be adjusted according to the Doppler shift to improve the ranging accuracy.

[0259] Environmental compensation: The speed of sound is corrected in real time through the temperature sensor to adapt to the ranging requirements under different water temperature conditions.

[0260] (2) Three-dimensional coordinate measurement technology of hole wall.

[0261] The system (such as Figure 7 The core of this technology (shown in Figure 1) is to measure an object's attitude (pitch, roll, and yaw) and acceleration using inertial sensors, combine this with ranging data from underwater acoustic sensors, and apply sensor fusion algorithms to construct a three-dimensional coordinate system. This allows the system to dynamically and accurately track an object's position changes in three-dimensional space.

[0262] a. Core sensor.

[0263] ① Inertial Measurement Unit (IMU): The MPU6050 is used, featuring a ±2000dps gyroscope and a ±16g accelerometer. This sensor accurately measures triaxial acceleration and angular velocity, providing the system with key attitude and acceleration information about an object's motion. This is a crucial foundation for the system's precise measurement.

[0264] ②Hydroacoustic sensor:

[0265] A hydroacoustic sensor with a frequency range of 50-300kHz was selected. The ultrasonic transducer was moved vertically along the pile hole, transmitting and receiving acoustic signals to measure cross-sectional data at different heights. This provided raw data for functions such as 3D image reconstruction, cavity collapse location and shape analysis, and pile hole verticality determination.

[0266] ③ Microcontroller: The Arduino UNO R3, with integrated USB communication, is responsible for data acquisition and preprocessing. It collects and initially processes data from the IMU and underwater acoustic sensor for subsequent in-depth analysis and calculations.

[0267] ④ Magnetometer (HMC5883L): Used to calibrate the IMU's yaw angle. Since the IMU's yaw angle may drift over time, the magnetometer uses the characteristics of the Earth's magnetic field to correct the IMU's yaw angle, improving the system's measurement accuracy.

[0268] ⑤ High-precision clock: Use TDC (Time-to-Digital Converter) or PLL phase-locked loop to achieve nanosecond time measurement to ensure ranging accuracy.

[0269] b. Implementation steps:

[0270] Attitude Estimation (IMU Data Processing): Attitude calculation uses quaternion technology to fuse gyroscope and accelerometer data to calculate the sensor's Euler angles (pitch angle θ, roll angle φ, and yaw angle ψ). Quaternion attitude calculation accurately obtains real-time object attitude information. Combined with the IMU's attitude angles, the underwater acoustic sensor's ranging direction is converted to a global coordinate system. This process combines the distance information measured by the underwater acoustic sensor with the attitude information provided by the IMU, providing accurate position increment data for three-dimensional coordinate calculation.

[0271] An initial coordinate origin is set, such as the center of the pile hole bottom. This initial point provides a benchmark for subsequent coordinate calculations. Then, the attitude angle and distance data are combined to calculate the 3D displacement increments. Finally, the final coordinates are obtained by accumulating the displacements. Through this iterative process, the system can obtain the coordinate position of the measured point in 3D space in real time.

[0272] Error compensation technology: The accelerometer's zero bias is corrected using the gravity vector, and the gyroscope's yaw drift is calibrated using a magnetometer. This calibration process can effectively reduce the error incurred during long-term IMU use and improve its measurement accuracy.

[0273] c. Application layer display.

[0274] (1) Pile hole measurement system.

[0275] like Figure 8 As shown, this application layer efficiently generates 3D graphics of pile borehole walls. Leveraging advanced 3D modeling technology, it presents complex pile borehole structures in an intuitive, three-dimensional manner. Users can freely view every detail of the pile borehole through rotation, zooming, and other operations, enabling comprehensive, multi-angle observation. In addition to 3D graphics, the application layer also supports the display of cross-sectional images at any height. Users simply specify the desired height, and the system quickly generates the corresponding cross-sectional image, helping them understand the specific shape and characteristics of the pile borehole at that height. Furthermore, the application layer can display longitudinal sections at any angle. Whether along the pile borehole axis or at any other angle, users can easily obtain longitudinal section images, providing powerful support for in-depth analysis of the pile borehole structure. For safety analysis, the application layer intelligently identifies and identifies the location and shape of collapses, helping users promptly identify potential safety hazards. Furthermore, through precise calculation algorithms, the application layer can calculate the overflow coefficient to determine the pile borehole's overflow status, providing a scientific basis for construction. Verticality is a key indicator of pile borehole quality. Through precise measurement and calculation, the application layer accurately determines the verticality of the pile borehole, ensuring that project quality meets regulatory requirements. Finally, the application layer also supports the calculation of volume values ​​at any height, providing users with comprehensive pile hole volume data and providing strong support for engineering design and construction.

[0276] (2) Construction progress monitoring.

[0277] The core of construction progress monitoring lies in using image processing technology to automatically identify key construction nodes, such as whether concrete pouring is complete, and calculate the construction progress percentage based on the number of completed key construction nodes. The specific steps are as follows: Data preparation: preparing image data for different key construction nodes and labeling their types; model training: feeding the labeled construction node image data into the model for training; model application: feeding the system's real-time image data into the model, which automatically detects key construction nodes.

[0278] The above-described embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention fall within the protection scope of the present invention.

Claims

1. A bored pile construction risk analysis method, characterized in that: The steps include: The accident tree analysis method is used to analyze the risks in the bored pile construction process. The potential accidents caused by the risks are regarded as the top events of bored pile construction risks. The intermediate events and basic events of the accidents are analyzed based on the top events. And build an accident tree based on top events, intermediate events and basic events; Use Boolean algebra to find the minimum cut set of the top event in the fault tree; Draw the dual tree of the fault tree based on the minimum cut set, use Boolean algebra to solve the dual tree, and obtain the minimum path set for the top event to occur; The structural importance of basic events to top events is determined by the number of times basic events appear in the minimum cut set or minimum path set; The risk factors for the occurrence of the top event are determined by the minimum cut set, the minimum path set or the structural importance.

2. The bored pile construction risk analysis method according to claim 1, characterized in that: The accident tree analysis method is used to determine the top events of bored pile construction risks. Based on the top events, the intermediate events and basic events of the accident are analyzed, including the following steps: Use the accident tree analysis method to identify the risks in the bored pile construction process and determine the accidents that may occur; Analyze the causes and consequences of the accident, identify the basic events that led to the accident, and list the causal relationships between the events based on the principles of the accident; Determine the direct and potential causes of the accident based on the causal relationship between various events; The accident is regarded as the top event, and the direct cause and potential cause of the accident are regarded as the intermediate event and basic event respectively; The top events, intermediate events and basic events are connected with logical symbols to obtain a constructed accident tree.

3. The bored pile construction risk analysis method according to claim 2, characterized in that: The top event is a bored pile accident T. The intermediate events include serious quality defects in the engineering entity P1, chaotic construction site management P2, the supervision unit's failure to perform supervision duties P3, and problems with the steel cage B1. The basic events include untimely concrete pouring X1, unqualified bored pile foundation X2, immature technical plan X3, failure to conduct technical briefing X4, unlicensed workers X5, lack of a quality assurance system X6, failure to verify the qualifications of the on-site construction unit X7, failure to promptly stop illegal construction X8, failure to conduct reinforcement inspection before lifting the steel cage X9, and direct use of wire rope to lift the steel cage X 10 , The size of the steel cage is not suitable X 11 and steel cage quality difference X 12 .

4. The bored pile construction risk analysis method according to claim 3, characterized in that: The logical symbols include "OR gate" and "AND gate".

5. The bored pile construction risk analysis method according to claim 4, characterized in that: The steps for solving the minimum cut set of the top event in the fault tree using Boolean algebra are as follows: starting from the top event, replace the previous level event with the next level event in a certain order, where the events connected by "OR gates" are arranged in columns, and the events connected by "AND gates" are arranged in rows, and the replacement is carried out level by level until all are represented by basic events. The calculation formula of the minimum cut set is: T=P1P2P3 =(X1+B1+X2)(X3+X4+X5+X6)(X7+X8) =(X1+X9+X 10 +X 11 +X 12 +X2)(X7+X8)(X3+X4+X5+X6) =X1X3X7+X1X3X8+X1X4X7+X1X4X8+X1X5X7+X1X5X8+X1X6X7+X1X6X8+X2X3X7+X2X3X8+X2X4X7+X2X4X8+X2X5X7+X2X5X8+X2X6X7+X2X6X8+X9X3X7+X9X3X8+X9X4X7+X9X4X8+X9X5X7+X9X5X8+X9X6X7+X9X6X8+X 10 X3X7+X 10 X3X8+X 10 X4X7+X 10 X4X8+X 10 X5X7+X 10 X5X8+X 10 X6X7+X 10 X6X8+X 11 X3X7+X 11 X3X8+X 11 X4X7+X 11 X4X8+X 11 X5X7+X 11 X5X8+X 11 X6X7+X 11 X6X8+X 12 X3X7+X 12 X3X8+X 12 X4X7+X 12 X4X8+X 12 X5X7+X 12 X5X8+X 12 X6X7+X 12 X6X8; In the formula, T is the top event, which is a bored pile accident; P1 is the existence of serious quality defects in the engineering entity; P2 is the chaotic management of the construction site; P3 is the failure of the supervision unit to perform its supervision duties; B1 is the problem of the steel cage; X1 is the basic event, including the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X4 is the lack of technical briefing; X5 is the unlicensed operation of the operator; X6 is the lack of a quality assurance system; X7 is the failure to verify the qualifications of the on-site construction unit; X8 is the failure to stop the illegal construction in time; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X4 is the failure to conduct technical briefing; X5 is the failure of the operator to work without a license; X6 is the lack of a quality assurance system; X7 is the failure to verify the qualifications of the on-site construction unit; X8 is the failure to stop the illegal construction in time; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the basic event, which includes the untimely concrete pouring; X2 is the unqualified bored pile foundation; X3 is the immature technical solution; X9 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the failure to conduct technical briefing; X1 is the failure to conduct technical briefing; X1 is the failure to conduct reinforcement inspection before lifting the steel cage; X1 is the basic event, which includes the untimely concrete pouring; X1 is the failure to 10 To directly use wire rope to lift the steel cage, X 11 The size of the steel cage is not suitable, X 12 The quality of the steel cage is poor.

6. The bored pile construction risk analysis method according to claim 5, characterized in that: The minimum cut set for the occurrence of the top event is 48 groups, specifically: E1={X1,X3,X7}, E2={X1,X3,X8}, E3={X1,X4,X7}, E4={X1,X4,X8}, E5={X1,X5,X7}, E6={X1,X5,X8}, E7={X1,X6,X7}, E8={X1,X6,X8}, E9={X2,X3,X7},E 10 ={X2,X3,X8},E 11 ={X2,X4,X7},E 12 ={X2,X4,X8}, E 13 ={X2,X5,X7},E 14 ={X2,X5,X8},E 15 ={X2,X6,X7},E 16 ={X2,X6,X8}, E 17 ={X9,X3,X7},E 18 ={X9,X3,X8},E 19 ={X9,X4,X7},E 20 ={X9,X4,X8}, E 21 ={X9,X5,X7},E 22 ={X9,X5,X8},E 23 ={X9,X6,X7},E 24 ={X9,X6,X8}, E 25 ={X 10 ,X3,X7},E 26 ={X 10 ,X3,X8},E 27 ={X 10 ,X4,X7},E 28 ={X 10 ,X4,X8}, E 29 ={X 10 ,X5,X7},E 30 ={X 10 ,X5,X8},E 31 ={X 10 ,X6,X7},E 32 ={X 10 ,X6,X8}, E 33 ={X 11 ,X3,X7},E 34 ={X 11 ,X3,X8},E 35 ={X 11 ,X4,X7},E 36 ={X 11 ,X4,X8}, E 37 ={X 11 ,X5,X7},E 38 ={X 11 ,X5,X8},E 39 ={X 11 ,X6,X7},E 40 ={X 11 ,X6,X8}, E 41 ={X 12 ,X3,X7},E 42 ={X 12 ,X3,X8},E 43 ={X 12 ,X4,X7},E 44 ={X 12 ,X4,X8}, E 45 ={X 12 ,X5,X7},E 46 ={X 12 ,X5,X8},E 47 ={X 12 ,X6,X7},E 48 ={X 12 ,X6,X8}。 7. The bored pile construction risk analysis method according to claim 5, characterized in that: The calculation formula of the minimum path set is: T * =P1 * +P2 * +P3 * =(X1 * B1 * X2 * )+(X3 * X4 * X5 * X6 * )+(X7 * X8 * ) =(X1 * X9 * X 10 * X 11 * X 12 * X2 * )+(X3 * X4 * X5 * X6 * )+(X7 * X8 * ); Where, T * 、P1 * 、P2 * 、P3 * 、B1 * 、X1 * 、X2 * 、X3 * 、X4 * 、X5 * 、X6 * 、X7 * 、X8 * 、X9 * 、X 10 * 、X 11 * and X 12 * They are T, P1, P2, P3, B1, X1, X2, X3, X4, X5, X6, X7, X8, X9, X 10 、X 11 and X 12 The dual tree of The minimum path set for the occurrence of the top event is 3 groups, specifically: E1 * ={X1 * X9 * ,X 10 * X 11 * X2 * },E2 * ={X3 * X4 * X5 * X6 * },E3 * ={X7 * X8 * }。 8. The bored pile construction risk analysis method according to claim 1, characterized in that: The determination formula of the structural importance is: Where: I(i) is the basic event X i Judgment value of structural importance; X i ∈K j The basic event Xi belongs to the minimum cut set or minimum path set of Kj; n i For basic event X i The number of basic events contained in the minimum cut set or minimum path set.

9. A bored pile construction risk analysis system, characterized in that: include: The accident tree construction module is used to analyze the risks in the bored pile construction process using the accident tree analysis method. The potential accidents caused by the risks are regarded as the top events of bored pile construction risks. The intermediate events and basic events of the accidents are analyzed based on the top events. And build an accident tree based on top events, intermediate events and basic events; Minimum cut set acquisition module, used to solve the minimum cut set of the top event in the fault tree using Boolean algebra method; The minimum path set acquisition module is used to draw the dual tree of the fault tree by utilizing the duality of the minimum path set and the minimum cut set, and solve the fault tree using Boolean algebra to obtain the minimum path set for the occurrence of the top event; A structural importance acquisition module is used to determine the structural importance of basic events to top events based on the number of times the basic events appear in the minimum cut set or the minimum path set; The risk determination module is used to determine the risk factors of the top event through the minimum cut set, minimum path set or structural importance.

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