Expressway construction safety risk assessment system based on knowledge graph

Abstract

The invention discloses an expressway construction safety risk assessment system based on a knowledge graph, and the system comprises the following steps: a multi-source construction data collection module which is used for forming a construction safety original data set; the risk state mapping module is used for mapping and generating a construction safety risk state set; the construction safety knowledge map module is used for constructing an expressway construction safety domain knowledge map; the half-sequence risk state space construction module is used for constructing a construction safety half-sequence risk state space; the reachable risk state analysis module is used for determining a reachable construction safety risk state subspace; the anti-fact half-sequence risk space reconstruction module is used for reconstructing an anti-fact half-sequence risk state space; the half-sequence structure fracture identification module is used for identifying a half-sequence structure fracture phenomenon; and the instability state judgment module is used for outputting a risk judgment result. Based on the knowledge graph and the semi-order state structure, construction safety risk assessment and judgment are achieved, and the method has the advantages of accuracy and interpretability.

Description

Technical Field

[0001] This invention relates to the field of highway construction safety management technology, and in particular to a knowledge graph-based highway construction safety risk assessment system. Background Technology

[0002] During highway construction, the construction procedures are complex and the working environment is dynamically changing. Construction safety risks are affected by a variety of factors, including the arrangement of procedures, traffic organization, equipment operation, personnel operations, and environmental conditions. Existing construction safety risk assessment technologies are usually based on empirical rules, statistical analysis, or risk index quantification methods to score, classify, or issue early warnings for construction safety risks. Some technologies introduce information systems or intelligent algorithms to summarize and analyze multi-source construction data, but overall, they still focus on the numerical expression of risk levels.

[0003] However, the aforementioned existing technologies primarily focus on assessing the magnitude of risk, making it difficult to characterize the structural evolution of construction safety risks under multiple engineering constraints. In particular, they struggle to determine whether, under specific combinations of construction conditions, construction safety risks have entered a structurally unavoidable state of instability. Existing methods typically lack the ability to systematically model the complex constraint relationships between construction elements and are also ill-equipped to analyze the reversibility of risk structures under hypothetical changes in construction conditions. Consequently, they fail to effectively identify the critical stages in which construction safety risks transition from controllable to unavoidable.

[0004] Therefore, how to provide a knowledge graph-based highway construction safety risk assessment system is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] One objective of this invention is to propose a knowledge graph-based highway construction safety risk assessment system. This invention, based on knowledge graphs and semi-ordered state structures, enables the assessment and determination of construction safety risks, and possesses advantages in accuracy and interpretability.

[0006] A knowledge graph-based highway construction safety risk assessment system according to an embodiment of the present invention includes the following steps:

[0007] The multi-source construction data acquisition module is used to acquire multi-source construction data involving safety risks during highway construction, and record the corresponding time and spatial location identifiers to form a set of original construction safety data.

[0008] The risk status mapping module is used to map raw construction safety data into a set of construction safety risk statuses.

[0009] The construction safety knowledge graph module is used to build a knowledge graph in the field of highway construction safety.

[0010] The semi-order risk state space construction module is used to determine the reachable construction safety risk state subspace in the construction safety semi-order risk state space under the current construction conditions.

[0011] The reachability risk state analysis module is used to perform state reachability analysis based on the construction event sequence to determine the reachable construction safety risk state subspace.

[0012] The Counterfactual Semi-Order Risk Space Reconstruction Module is used to perform counterfactual stripping processing within the reachable construction safety risk state subspace and reconstruct the counterfactual semi-order risk state space.

[0013] The semi-order structural fracture identification module is used to identify whether structural fracture occurs under counterfactual conditions in the construction safety semi-order risk state space.

[0014] The instability state determination module is used to determine whether the construction safety risk has entered an unavoidable instability state in the structure when there is a semi-sequence structural fracture phenomenon and there is no reachable path to retreat to a state with minimal risk of safety, and outputs the risk determination result.

[0015] Optionally, the risk status mapping module includes:

[0016] Based on the original set of construction safety data, time alignment processing is performed on the multi-source construction data according to a unified time identifier. The multi-source construction data includes construction procedure data, traffic organization data, equipment configuration data, personnel operation data, and environmental condition data, to obtain the construction procedure status, traffic organization status, equipment operation status, personnel operation status, and environmental condition status that correspond one-to-one with each time identifier.

[0017] Under the same time identifier, the construction process status, traffic organization status, equipment operation status, personnel operation status and environmental condition status are associated based on the spatial location identifier. Based on the status correspondence between the statuses, the construction status is mapped to the risk status, and each type of construction status is mapped to the corresponding component in the construction safety risk status vector.

[0018] Combine the components corresponding to the same time identifier and the same spatial location identifier to generate a construction safety risk status vector corresponding to the time identifier and spatial location identifier.

[0019] The construction safety risk status vectors corresponding to different time markers and different spatial location markers are aggregated to form a construction safety risk status set.

[0020] Optionally, the construction safety knowledge graph module includes:

[0021] Based on the original construction safety data set, entity recognition processing is performed on the multi-source construction data involved in the highway construction process to determine the construction element entities. Entity recognition processing is also performed on the data related to construction safety risks to determine the construction risk entities. Corresponding entity identifiers are generated for each construction element entity and each construction risk entity.

[0022] Based on the sequential and dependent relationships of construction procedures in the construction process, procedure constraint relationships are established between construction element entities, and the procedure constraint relationships are associated with the corresponding construction element entities;

[0023] Based on the correspondence between construction element entities and construction risk entities in terms of spatial location identification, a spatial constraint relationship is constructed between construction element entities and construction risk entities, and the spatial constraint relationship is associated with the corresponding construction element entities and construction risk entities.

[0024] Based on the correspondence between construction element entities and construction risk entities in terms of time identifiers, a time constraint relationship is constructed between construction element entities and construction risk entities, and the time constraint relationship is associated with the corresponding construction element entities and construction risk entities.

[0025] Based on the safety control conditions formed during the construction safety management process, a safety constraint relationship is established between the construction element entity and the construction risk entity, and the safety constraint relationship is associated with the corresponding construction element entity and construction risk entity;

[0026] By unifying the organization of construction element entities, construction risk entities, and process constraints, spatial constraints, temporal constraints, and safety constraints, a knowledge graph for the field of highway construction safety is formed.

[0027] Optionally, the semi-order risk state space construction module includes:

[0028] Based on the set of construction safety risk states, any two construction safety risk states are selected as risk state pairs to be judged, and the construction safety risk state vectors corresponding to each construction safety risk state in the risk state pairs to be judged are obtained.

[0029] For the risk status pairs to be determined, based on the knowledge graph of highway construction safety, the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship corresponding to the construction safety risk status are extracted, and the constraint relationship is organized into constraint combination;

[0030] Under the constraints, based on the satisfying and covering relationship between the two construction safety risk states in the constraint combination, it is determined whether one of the construction safety risk states forms a constraint inclusion for the other construction safety risk state under the constraint combination.

[0031] If the constraints of determining one construction safety risk state cover the other construction safety risk state, and there is no constraint relationship that reverses the coverage relationship, then a one-way dominance relationship is determined between the two construction safety risk states, and the one-way dominance relationship is recorded as a semi-order relationship between the construction safety risk states.

[0032] For all construction safety risk states in the set of construction safety risk states, the dominance judgment process is repeatedly executed, the generated semi-order relations are collected, and a construction safety semi-order risk state space is constructed based on the semi-order relations.

[0033] Optionally, the reachability risk status analysis module includes:

[0034] Under the current construction conditions, based on a unified time identifier, the construction safety risk state vectors corresponding to each construction safety risk state in the construction safety risk state set are arranged in chronological order, and the process of changes in the construction safety risk state vectors under adjacent time identifiers is identified as construction events, forming a construction event sequence arranged in chronological order.

[0035] In the construction safety semi-sequence risk state space, the construction safety risk state corresponding to the start time identifier of the construction event sequence is selected as the initial construction safety risk state;

[0036] For each construction event in the construction event sequence, in the construction safety semi-order risk state space, based on the unidirectional domination constraint defined by the semi-order relationship, it is determined whether the construction safety risk state change caused by the construction event maintains the semi-order relationship without being destroyed, and only the construction safety risk state change that maintains the semi-order relationship is retained.

[0037] Based on the changes in construction safety risk status that maintain the semi-order relationship, the construction safety risk status that can be reached from the initial construction safety risk status through the construction event sequence is gradually aggregated to form a state arrival set.

[0038] The set of states that can be reached is defined as the subspace of the reachable construction safety risk states under the current construction conditions.

[0039] Optionally, the counterfactual semi-order risk space reconstruction module includes:

[0040] The reachable construction safety risk state subspace is used as the initial state range for counterfactual analysis, and the construction elements or construction events that are the objects of counterfactual analysis are determined within the initial state range.

[0041] Based on the knowledge graph of highway construction safety, the construction element entity or construction risk entity corresponding to the counterfactual analysis object is located, and the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship directly related to the construction element entity or construction risk entity are extracted to form a set of constraint relationships to be stripped.

[0042] While keeping all other construction conditions except for the counterfactual analysis object unchanged, the set of constraint relations to be stripped is subjected to counterfactual stripping processing to generate counterfactual construction conditions;

[0043] Under counterfactual construction conditions, the subspace of achievable construction safety risk states is used as the only allowed set of states. Based on the constraint combination after removing constraints, the dominance relationship between construction safety risk states is re-determined to generate a semi-order relation set consistent with the counterfactual construction conditions.

[0044] The semi-order relations in the original construction safety semi-order risk state space are replaced with a set of semi-order relations, and the structural relations between construction safety risk states are reorganized based on the replaced set of semi-order relations to construct the counterfactual semi-order risk state space.

[0045] Optionally, the semi-sequential structural fracture identification module includes:

[0046] The reachable construction safety risk state subspace is used as the sole scope of the semi-order structure determination. Within this scope, based on the construction safety semi-order risk state space, the set of minimal risk states that are not dominated by any other construction safety risk state under the semi-order relation constraint is identified.

[0047] Within the defined scope of the reachable construction safety risk state subspace, based on the counterfactual semi-order risk state space, for each construction safety risk state in the reachable construction safety risk state subspace, it is determined whether it can still form a lower bound constraint relationship with at least one minimal risk state under the semi-order relation constraint.

[0048] When it is determined that at least one construction safety risk state can no longer form a lower bound constraint relationship with any minimal risk state in the counterfactual semi-order risk state space, it is determined that the construction safety risk state has experienced a semi-order relationship dominance connectivity failure under counterfactual conditions.

[0049] In the reachable construction safety risk state subspace, if it is determined that there is at least one construction safety risk state in which a semi-order relation dominates the failure of connectivity, then the construction safety semi-order risk state space is determined to have a semi-order structure fracture phenomenon under counterfactual conditions.

[0050] Optionally, the instability state determination module includes:

[0051] The subspace of the achievable construction safety risk state is used as the sole scope of the judgment on the unavoidable structural instability. Within the scope of the judgment, the semi-order structural fracture phenomenon determined by the previous steps is accepted as the premise for structural judgment.

[0052] Within the defined subspace of the reachable construction safety risk state, for each construction safety risk state, based on the counterfactual semi-order risk state space, under the semi-order relation constraint, it is determined whether there is still a possibility of structural regression.

[0053] When it is determined that there is no possibility of structural regression in the counterfactual semi-order risk state space, it is determined that the construction safety risk state cannot be regressed to the safety minimum risk state through the semi-order relationship under counterfactual conditions.

[0054] In the subspace of reachable construction safety risk states, if each construction safety risk state satisfies the condition that it cannot regress to the state of minimum safety risk through the semi-order relationship, and the semi-order structural fracture phenomenon has been confirmed, then it is determined that the construction safety risk has entered an unavoidable structural instability state, and the corresponding risk judgment result is output.

[0055] Optionally, the determination of the state of minimal safety risk includes:

[0056] In the constructed semi-order risk state space of construction safety, based on the established semi-order relationship, a set of candidate minimum risk states is determined for the identified minimum risk states.

[0057] For each minimum risk state in the candidate minimum risk state set, the determined constraint combination corresponding to the minimum risk state is invoked to determine whether the constraint combination simultaneously meets the construction safety conditions under the current construction conditions.

[0058] When it is determined that the combination of constraints meets the conditions for the establishment of construction safety, the corresponding minimum risk state is determined as the minimum risk state of safety.

[0059] If any condition in the combination of constraints does not meet the conditions for the establishment of construction safety, the corresponding minimum risk state shall be excluded as the minimum risk state for safety.

[0060] At least one state with minimal safety risk is identified as the safety reference state upon which the semi-order relation regression determination and the structural instability determination are based.

[0061] The beneficial effects of this invention are:

[0062] This invention fundamentally improves the assessment method of highway construction safety risks by introducing a technical approach that combines knowledge graphs with a semi-ordered risk state space. By uniformly modeling multi-source construction data such as construction procedures, traffic organization, equipment operation, personnel operations, and environmental conditions, and explicitly expressing the process constraints, spatial constraints, temporal constraints, and safety constraints between construction elements and construction risks in the knowledge graph, construction safety risks are no longer the result of the superposition of isolated indicators, but a structured risk state jointly defined by multiple engineering constraints. This approach can characterize the structural environment in which construction safety risks exist at the overall level, providing a stable and interpretable basis for subsequent risk evolution analysis.

[0063] Furthermore, this invention constructs a semi-order risk state space for construction safety by using a constraint combination-based dominance decision, transforming construction safety risks into comparable structural state problems. This allows risk states under different construction conditions to have clear evolution directions and constraint boundaries. Based on this, an event-driven state accessibility analysis is introduced to prune the construction safety risk state space, retaining only the risk state subspace actually accessible under the current construction conditions. This effectively avoids a large number of hypothetical risk states unrelated to the actual construction process in traditional risk assessments, thereby improving the relevance and reliability of the assessment results.

[0064] Meanwhile, this invention, through a counterfactual stripping mechanism, selectively eliminates the constraints imposed by specific construction elements or events while keeping the overall construction conditions unchanged, and reconstructs the counterfactual semi-order risk state space accordingly. This allows risk assessment to move beyond being limited to predetermined construction conditions and to analyze the impact of changes in key constraints on the risk structure.

[0065] By comparing and analyzing the original semi-order structure with the counterfactual semi-order structure, it is possible to identify whether the semi-order structure has fractured, and to determine from the structural level whether the construction safety risk has lost a safe path of reversibility. Furthermore, by combining the structural reversal judgment of the minimal risk state, this invention can accurately identify whether the construction safety risk has entered the stage of unavoidable structural instability. Thus, it provides a decision support method for construction safety management based on the solvability and reversibility of risk structure, effectively improving the foresight, reliability and engineering practical value of highway construction safety risk assessment. Attached Figure Description

[0066] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0067] Figure 1 This is an overall flowchart of a knowledge graph-based highway construction safety risk assessment system proposed in this invention.

[0068] Figure 2 This is a schematic diagram illustrating the relationship between the construction safety knowledge graph and the construction safety semi-order risk state space in a knowledge graph-based highway construction safety risk assessment system proposed in this invention.

[0069] Figure 3 This is a schematic diagram of the counterfactual semi-order risk state space reconstruction and semi-order structure fracture identification in a knowledge graph-based highway construction safety risk assessment system proposed in this invention. Detailed Implementation

[0070] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0071] refer to Figures 1-3 A knowledge graph-based highway construction safety risk assessment system includes the following steps:

[0072] The multi-source construction data acquisition module is used to acquire multi-source construction data involving safety risks during highway construction. The multi-source construction data includes construction procedure data, traffic organization data, equipment configuration data, personnel operation data, and environmental condition data. It records unified time and spatial location identifiers for various types of multi-source construction data to form a set of original construction safety data.

[0073] The risk status mapping module is used to execute the status mapping rules from construction status to risk status based on the original construction safety data set, and to map the construction process status, traffic organization status, equipment operation status, personnel operation status and environmental condition status into construction safety risk status vectors, forming a construction safety risk status set.

[0074] The construction safety knowledge graph module is used to construct a knowledge graph in the field of highway construction safety. The knowledge graph includes construction element entities, construction risk entities, and the process constraint relationships, spatial constraint relationships, temporal constraint relationships, and safety constraint relationships between construction element entities and construction risk entities.

[0075] The semi-order risk state space construction module is used to perform dominance judgment processing on any two construction safety risk states in the construction safety risk state set based on the constraint relationship in the knowledge graph of highway construction safety, generate semi-order relationship between construction safety risk states, and construct construction safety semi-order risk state space.

[0076] The reachability risk state analysis module is used to perform state reachability analysis on the construction safety semi-sequence risk state space under the current construction conditions, based on the construction event sequence formed by the change of the construction safety risk state vector over time, and to determine the reachable construction safety risk state subspace under the current construction conditions.

[0077] The Counterfactual Semi-Order Risk Space Reconstruction Module is used to perform counterfactual stripping processing on at least one construction element or construction event based on the reachable construction safety risk state subspace, while keeping the other construction conditions unchanged, to generate corresponding counterfactual construction conditions, and to reconstruct the counterfactual semi-order risk state space with the reachable construction safety risk state subspace as the initial state range.

[0078] The semi-order structure fracture identification module is used to perform structural comparison analysis on the construction safety semi-order risk state space and the counterfactual semi-order risk state space within the limited scope of the reachable construction safety risk state subspace, identify the connectivity changes in the semi-order relationship, and determine whether there is a semi-order structure fracture phenomenon.

[0079] The instability state determination module is used to determine the existence of a semi-order structural fracture phenomenon in the reachable construction safety risk state subspace. If, starting from any construction safety risk state in the reachable construction safety risk state subspace, there is no reachable path in the counterfactual semi-order risk state space that can be retreated to the state of minimum safety risk, the module determines that the construction safety risk has entered an unavoidable structural instability state and outputs the corresponding risk determination result.

[0080] In this embodiment, the risk status mapping module includes:

[0081] Based on the original set of construction safety data, time alignment processing is performed on the multi-source construction data according to a unified time identifier. The multi-source construction data includes construction procedure data, traffic organization data, equipment configuration data, personnel operation data, and environmental condition data, resulting in construction procedure status, traffic organization status, equipment operation status, personnel operation status, and environmental condition status that correspond one-to-one with each time identifier.

[0082] Under the same time identifier, the construction process status, traffic organization status, equipment operation status, personnel operation status and environmental condition status are associated based on the spatial location identifier. Based on the status correspondence between the statuses, the construction status is mapped to the risk status, and each type of construction status is mapped to the corresponding component in the construction safety risk status vector.

[0083] The state mapping process specifically includes: under the same constraints of time and spatial location, firstly, based on the state correspondence between construction procedure state, traffic organization state, equipment operation state, personnel operation state, and environmental condition state, semantic distinctions are made for various construction states. For each type of construction state, according to its role in construction safety risk, it is mapped to the corresponding component in the construction safety risk state vector, so that different construction states have fixed positions and clear semantics in the risk state vector. During the mapping process, the consistency of time and spatial location identifiers of various construction states is maintained, so that the mapped construction safety risk state vector can fully reflect the combination of construction states under specific time and space.

[0084] Combine the components corresponding to the same time identifier and the same spatial location identifier to generate a construction safety risk status vector corresponding to the time identifier and spatial location identifier.

[0085] The construction safety risk status vectors corresponding to different time markers and different spatial location markers are aggregated to form a construction safety risk status set.

[0086] In this embodiment, the construction safety knowledge graph module includes:

[0087] Based on the original construction safety data set, entity recognition processing is performed on the multi-source construction data involved in the highway construction process to determine the construction element entities. Entity recognition processing is also performed on the data related to construction safety risks to determine the construction risk entities. Corresponding entity identifiers are generated for each construction element entity and each construction risk entity.

[0088] Based on the sequential and dependent relationships of construction procedures in the construction process, procedure constraint relationships are established between construction element entities, and the procedure constraint relationships are associated with the corresponding construction element entities;

[0089] The specific steps of constructing process constraint relationships include: identifying the sequential relationships between construction processes based on their order and operational dependencies in the construction process; establishing process constraint relationships that represent prerequisite conditions and prohibition of reverse execution for construction processes with dependencies; associating process constraint relationships with corresponding construction element entities to form a structured constraint expression between construction processes.

[0090] Based on the correspondence between construction element entities and construction risk entities in terms of spatial location identification, a spatial constraint relationship is constructed between construction element entities and construction risk entities, and the spatial constraint relationship is associated with the corresponding construction element entities and construction risk entities.

[0091] The specific steps of constructing spatial constraint relationships include: identifying the spatial correspondence of construction element entities and construction risk entities in the construction area based on their spatial location identifiers; establishing spatial constraint relationships that represent spatial limitations for construction element entities and construction risk entities that have spatial overlap, spatial adjacency, or spatial scope association; and associating the spatial constraint relationships with the corresponding construction element entities and construction risk entities to form a spatial constraint expression.

[0092] Based on the correspondence between construction element entities and construction risk entities in terms of time identifiers, a time constraint relationship is constructed between construction element entities and construction risk entities, and the time constraint relationship is associated with the corresponding construction element entities and construction risk entities.

[0093] The construction of time constraint relationships specifically includes: identifying the correspondence between construction element entities and construction risk entities on the construction time axis based on the time identifiers corresponding to them; establishing time constraint relationships that represent time limits for construction element entities and construction risk entities with the same time identifier or overlapping time relationships; and associating the time constraint relationships with the corresponding construction element entities and construction risk entities to form a time-level constraint expression.

[0094] Based on the safety control conditions formed during the construction safety management process, a safety constraint relationship is established between the construction element entity and the construction risk entity, and the safety constraint relationship is associated with the corresponding construction element entity and construction risk entity;

[0095] The specific steps of constructing safety constraint relationships include: based on the safety control conditions formed during the construction safety management process, identifying the safety restriction relationships between construction element entities and construction risk entities; establishing safety constraint relationships representing safety restriction conditions for construction element entities and construction risk entities with safety control requirements; and associating the safety constraint relationships with the corresponding construction element entities and construction risk entities to form a constraint expression at the safety level.

[0096] By unifying the organization of construction element entities, construction risk entities, and process constraints, spatial constraints, temporal constraints, and safety constraints, a knowledge graph for the field of highway construction safety is formed.

[0097] In this embodiment, the semi-order risk state space construction module includes:

[0098] Based on the set of construction safety risk states, any two construction safety risk states are selected as risk state pairs to be judged, and the construction safety risk state vectors corresponding to each construction safety risk state in the risk state pairs to be judged are obtained.

[0099] For the risk status pairs to be determined, based on the knowledge graph of highway construction safety, the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship corresponding to the construction safety risk status are extracted, and the constraint relationship is organized into a constraint combination to describe the feasibility of the construction status;

[0100] Under the constraints, based on the satisfying and covering relationship between the two construction safety risk states in the constraint combination, it is determined whether one of the construction safety risk states forms a constraint inclusion for the other construction safety risk state under the constraint combination.

[0101] The fulfillment of the coverage relationship means that, under the same constraint combination, in two construction safety risk states, the satisfaction of each constraint condition in the constraint combination by one construction safety risk state is no less than that by the other construction safety risk state in terms of the scope of constraint validity. That is, for each constraint condition in the constraint combination, if the latter construction safety risk state satisfies the constraint condition, then the former construction safety risk state also satisfies the constraint condition, and there is no constraint condition that is violated by the former construction safety risk state but satisfied by the latter construction safety risk state.

[0102] Constraint inclusion is the specific set relation that corresponds to the validity of a covering relationship. Specifically, under the constraints of a combination of constraints, the set of constraints satisfied by one construction safety risk state includes, in a set sense, the set of constraints satisfied by another construction safety risk state.

[0103] If the constraints of determining one construction safety risk state cover the other construction safety risk state, and there is no constraint relationship that reverses the coverage relationship, then a one-way dominance relationship is determined between the two construction safety risk states, and the one-way dominance relationship is recorded as a semi-order relationship between the construction safety risk states.

[0104] The unidirectional dominance relationship is used to describe the asymmetric comparability of two construction safety risk states on the constraint-satisfying structure. Its core is that one risk state is always no worse than the other risk state under given constraints, and the relationship cannot be reversed. This relationship reflects the directional priority between risk states on the constraint-satisfying structure, rather than a comparison of risk magnitude or risk level. It is used to characterize the leading and constrained relationship of risk states in structural evolution.

[0105] For all construction safety risk states in the set of construction safety risk states, the dominance judgment process is repeatedly executed, the generated semi-order relations are collected, and a construction safety semi-order risk state space is constructed based on the semi-order relations.

[0106] In this embodiment, the reachability risk status analysis module includes:

[0107] Under the current construction conditions, based on a unified time identifier, the construction safety risk state vectors corresponding to each construction safety risk state in the construction safety risk state set are arranged in chronological order, and the process of changes in the construction safety risk state vectors under adjacent time identifiers is identified as construction events, forming a construction event sequence arranged in chronological order.

[0108] In the construction safety semi-sequence risk state space, the construction safety risk state corresponding to the start time identifier of the construction event sequence is selected as the initial construction safety risk state;

[0109] For each construction event in the construction event sequence, in the construction safety semi-order risk state space, based on the unidirectional domination constraint defined by the semi-order relationship, it is determined whether the construction safety risk state change caused by the construction event maintains the semi-order relationship without being destroyed, and only the construction safety risk state change that maintains the semi-order relationship is retained.

[0110] Determining whether the change in construction safety risk status caused by the construction event maintains the semi-order relationship without being destroyed specifically includes: based on the relative order consistency of the risk status before and after the construction event in the established order structure. Specifically, it involves comparing the directional relationship of the risk status before and after the event in the constraint-satisfied structure, checking whether a new reverse priority relationship has appeared or the original directional relationship has disappeared. If the risk status remains in the structural position allowed by the original direction after the change, and no structural relationship conflicting with the existing direction has been introduced, then the order structure is considered to be maintained. If the change causes the directionality to reverse or the original direction can no longer be established, then the order structure is considered to be destroyed.

[0111] Based on the changes in construction safety risk status that maintain the semi-order relationship, the construction safety risk status that can be reached from the initial construction safety risk status through the construction event sequence is gradually aggregated to form a state arrival set.

[0112] The set of states that can be reached is defined as the subspace of the reachable construction safety risk states under the current construction conditions.

[0113] In this embodiment, the counterfactual semi-order risk space reconstruction module includes:

[0114] The reachable construction safety risk state subspace is used as the initial state range for counterfactual analysis, and the construction elements or construction events that are the objects of counterfactual analysis are determined within the initial state range.

[0115] Based on the knowledge graph of highway construction safety, the construction element entity or construction risk entity corresponding to the counterfactual analysis object is located, and the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship directly related to the construction element entity or construction risk entity are extracted to form a set of constraint relationships to be stripped.

[0116] While keeping all other construction conditions unchanged except for the object of counterfactual analysis, counterfactual stripping is performed on the set of constraints to be stripped, so that the set of constraints to be stripped no longer constrains the construction safety risk state, thereby generating counterfactual construction conditions.

[0117] The specific steps of counterfactual stripping include: using the existing risk state structure as a reference, selecting a single construction-related factor whose structural impact needs to be examined, and eliminating the constraints imposed by the factor without changing other construction conditions and related structures. During the stripping process, only the structural constraints directly related to the factor are rendered ineffective, while the remaining constraints remain unchanged. Based on this, the affected risk state relationships are locally adjusted to form a control structure that is consistent with the original structure in overall form but differs in local constraints. This structure is used to reveal the characteristics of the risk structure changes when the factor is missing.

[0118] Under counterfactual construction conditions, the reachable construction safety risk state subspace is used as the only allowed set of states. Based on the constraint combination after removing constraints, the dominance relationship between construction safety risk states is re-determined to generate a semi-order relation set consistent with the counterfactual construction conditions.

[0119] The re-determination specifically includes: for any two construction safety risk states, based on the constraint combination after removing constraints, re-examining the satisfaction of the two under each constraint condition, and determining whether there is still a constraint inclusion relationship or a covering relationship. When the original constraint relationship fails or the determination basis changes, the determination result in the original construction safety semi-order risk state space is no longer used. Instead, the constraint satisfaction structure under the current counterfactual conditions is used as the new determination basis to redetermine whether there is a unidirectional dominance relationship or no dominance relationship between the two construction safety risk states.

[0120] The semi-order relations in the original construction safety semi-order risk state space are replaced with a set of semi-order relations, and the structural relations between construction safety risk states are reorganized based on the replaced set of semi-order relations to construct the counterfactual semi-order risk state space.

[0121] In this embodiment, the semi-order structure fracture identification module includes:

[0122] The reachable construction safety risk state subspace is used as the sole scope of the semi-order structure determination. Within this scope, based on the construction safety semi-order risk state space, the set of minimal risk states that are not dominated by any other construction safety risk state under the semi-order relation constraint is identified.

[0123] Within the scope of the reachable construction safety risk state subspace, based on the counterfactual semi-order risk state space, for each construction safety risk state in the reachable construction safety risk state subspace, it is determined whether it can still form a lower bound constraint relationship with at least one minimal risk state under the semi-order relation constraint, in order to characterize the maintenance of dominant connectivity in the semi-order relation.

[0124] The formation of lower bound constraint relationships includes: in a given semi-order structure, a risk state can serve as a structural lower bound reference for another risk state, that is, the latter risk state is never superior to the former risk state in terms of constraint satisfaction structure, and its structural position is limited by the former risk state. This relationship is reflected in the fact that under the existing constraints, the structural evolution of the latter risk state cannot cross or bypass the lower bound state, but must be limited by the constraint range defined by the lower bound state, so that the lower bound state forms a constraint benchmark for it in terms of structure.

[0125] When it is determined that at least one construction safety risk state can no longer form a lower bound constraint relationship with any minimal risk state in the counterfactual semi-order risk state space, it is determined that the construction safety risk state has experienced a semi-order relationship dominance connectivity failure under counterfactual conditions.

[0126] In the reachable construction safety risk state subspace, if it is determined that there is at least one construction safety risk state in which a semi-order relation dominates the failure of connectivity, then the construction safety semi-order risk state space is determined to have a semi-order structure fracture phenomenon under counterfactual conditions.

[0127] In this embodiment, the instability state determination module includes:

[0128] The subspace of the achievable construction safety risk state is used as the sole scope of the judgment on the unavoidable structural instability. Within the scope of the judgment, the semi-order structural fracture phenomenon determined by the previous steps is accepted as the premise for structural judgment.

[0129] Within the defined subspace of the reachable construction safety risk state, for each construction safety risk state, based on the counterfactual semi-order risk state space, under the semi-order relation constraint, it is determined whether there is still a structural regression possibility that can make the construction safety risk state reach the safety minimum risk state through the semi-order relation to dominate regression.

[0130] When it is determined that there is no possibility of structural regression in the counterfactual semi-order risk state space, it is determined that the construction safety risk state cannot be regressed to the safety minimum risk state through the semi-order relationship under counterfactual conditions.

[0131] In the subspace of reachable construction safety risk states, if each construction safety risk state satisfies the condition that it cannot regress to the state of minimum safety risk through the semi-order relationship, and the semi-order structural fracture phenomenon has been confirmed, then it is determined that the construction safety risk has entered an unavoidable structural instability state, and the corresponding risk judgment result is output.

[0132] In this embodiment, the determination of a state with minimal safety risk includes:

[0133] In the constructed construction safety semi-order risk state space, based on the established semi-order relations, for the identified minimum risk states, a set of candidate minimum risk states is determined. The minimum risk state is a risk state that is not dominated by any other construction safety risk state under the constraints of the semi-order relations.

[0134] For each minimum risk state in the candidate minimum risk state set, the determined constraint combination corresponding to the minimum risk state is invoked to determine whether the constraint combination simultaneously meets the construction safety conditions under the current construction conditions.

[0135] When it is determined that the combination of constraints meets the conditions for the establishment of construction safety, the corresponding minimum risk state is determined as the minimum risk state of safety.

[0136] If any condition in the combination of constraints does not meet the conditions for the establishment of construction safety, the corresponding minimum risk state shall be excluded as the minimum risk state for safety.

[0137] At least one state with minimal safety risk is identified as the safety reference state upon which the semi-order relation regression determination and the structural instability determination are based.

[0138] Example 1: To verify the feasibility of the present invention in practice, the present invention was applied to...

[0139] To verify the feasibility of this invention in practice, it was applied to the actual construction safety management process of a highway reconstruction and expansion project. This highway is located on a major traffic artery with high traffic volume. During construction, multiple operations, including roadbed widening, bridge and culvert reinforcement, and adjustment of protective facilities, need to be carried out simultaneously without interrupting existing traffic. The construction site is constantly in a state of multiple overlapping processes, multiple parallel work areas, frequent adjustments to traffic organization, and a high density of equipment and personnel, resulting in significant dynamics and structural complexity in construction safety risks. Traditional methods relying on experience-based judgment or risk classification often only reflect the level of risk at a specific moment and are insufficient to identify whether construction safety has lost its structural safety evolution space under complex constraints. Therefore, they cannot provide a forward-looking basis for construction organization adjustments and risk intervention.

[0140] In this construction scenario, firstly, through the construction management system, on-site sensing equipment, and safety management records, information on construction procedures, traffic organization adjustments, equipment deployment and operation status, personnel work arrangements, and changes in environmental conditions are continuously collected, forming multi-source construction data covering the entire construction area and process. Each piece of data is accompanied by corresponding time and spatial location identifiers during collection to accurately reflect the combination of construction statuses at different times and locations. By uniformly organizing this multi-source construction data, a raw data set for construction safety is formed, providing a complete data foundation for subsequent analysis.

[0141] In practical applications, the system, based on the original construction safety data set, integrates and correlates the construction process status, traffic organization status, equipment operation status, personnel operation status, and environmental condition status at each time and spatial location of the construction site. Through state mapping, these construction states are mapped into construction safety risk state vectors with fixed structures and clear semantics. Each construction safety risk state vector corresponds to a specific combination of actual construction states at a particular time and location, thus achieving a structured expression of construction safety status. As the construction process progresses, the system continuously generates and aggregates construction safety risk state vectors at different times and spatial locations, forming a set of construction safety risk states that reflects the evolutionary characteristics of the entire construction process.

[0142] Based on this, the system constructs a knowledge graph for highway construction safety, representing key construction elements and safety risks involved in the construction process in a concrete way. It also establishes procedural, spatial, temporal, and safety constraints between these entities, reflecting the actual constraints of construction. Through this knowledge graph, the system can accurately depict the sequential dependencies between construction procedures, spatial limitations between different construction areas, overlapping of work activities along the timeline, and the control conditions imposed by construction safety management, thus grounding the analysis of construction safety risks in clear engineering semantic constraints.

[0143] Subsequently, based on the constraint relationships in the knowledge graph, the system performs dominance judgment on risk state pairs in the construction safety risk state set, constructing a semi-order risk state space for construction safety. In this space, construction safety risk states are no longer compared simply by numerical magnitude, but are organized through covering and inclusion relationships in the constraint satisfaction structure, thus forming a semi-order relationship that reflects the direction of risk state structural evolution. This semi-order risk state space truly reflects the structural location distribution of construction safety under complex constraint conditions.

[0144] As construction progresses, the system performs state reachability analysis in the semi-order risk state space of construction safety based on the construction event sequence formed by the change of the construction safety risk state vector over time. This analysis identifies which construction safety risk states are structurally reachable under the current construction conditions, thus forming a reachable construction safety risk state subspace. This subspace characterizes the entire range of structural states that construction safety risks may evolve to without altering existing construction conditions.

[0145] To further analyze the impact of key construction elements or events on the overall risk structure, the system performs counterfactual stripping on selected construction elements or events within the reachable construction safety risk state subspace. While keeping other construction conditions constant, the system selectively strips constraints directly associated with the chosen construction element or event, generating corresponding counterfactual construction conditions. Under these conditions, the system re-evaluates the dominance relationships between construction safety risk states, reconstructing the counterfactual semi-order risk state space. In this way, the system can simulate the overall changes in the construction safety risk structure when a certain construction factor changes or fails.

[0146] In practical applications, by structurally comparing the original construction safety semi-order risk state space with the counterfactual semi-order risk state space, the system identifies changes in connectivity within the semi-order relationships and determines whether semi-order structural fractures exist. When it is found that some construction safety risk states can no longer regress to any minimum safety risk state through semi-order relationships under counterfactual conditions, the system further determines that the construction safety risk has entered an unavoidable structural instability state and outputs a clear risk assessment prompt to construction management personnel.

[0147] Through continuous application in the aforementioned highway construction scenarios, it can be observed that the present invention significantly outperforms traditional methods in characterizing the evolution of construction safety risks under complex construction conditions. The system can identify the disappearance trend of the safety solution space at the structural level before construction risks manifest as obvious accident symptoms, providing a more forward-looking decision-making basis for construction organization adjustments, process rearrangements, and safety interventions. Furthermore, because the present invention is based on knowledge graphs and semi-order structures for analysis, the risk assessment process has good interpretability. Construction managers can clearly understand the key construction elements and changes in constraint relationships that lead to risk instability, thereby improving the pertinence and effectiveness of construction safety management.

[0148] Table 1. Comparison Results of Experiments on Safety Risk Assessment Methods for Highway Construction

[0149] As shown in Table 1, traditional risk classification methods mainly rely on historical experience and risk threshold determination, and can only provide early warnings of about 1.5 hours in advance, making it difficult to cope with the evolution of structural risks under complex construction conditions. Methods based on rules and statistical models extend the risk identification time to some extent, but are still limited by the completeness of the rules and the assumptions of the models.

[0150] In comparison, the method of this invention achieves a risk identification lead time of 3.1 hours, which is higher than the comparative method. This indicates that by constructing a semi-sequence risk state space for construction safety and introducing a counterfactual analysis mechanism, it is possible to identify the tendency of construction safety structures to become unstable in advance, before the risk has been numerically amplified.

[0151] In terms of the accuracy of structural instability identification, the method of this invention achieves 89%, which is significantly better than other methods. This result shows that the semi-order relation determination based on knowledge graph constraints can effectively avoid the limitations of judging risk based on a single indicator or local features, and accurately capture the evolutionary relationship between risk states at the structural level.

[0152] Meanwhile, the false alarm rate of the method of the present invention is significantly reduced to 6%, mainly because the introduction of the counterfactual semi-order risk state space can distinguish between short-term disturbances and structural instability, thereby reducing unnecessary risk warnings caused by temporary fluctuations.

[0153] The method of this invention demonstrates significant advantages in terms of adaptability to complex construction scenarios and interpretability of risk causes. By using a knowledge graph to uniformly model construction elements, risk entities, and their constraints, the risk assessment results can clearly correspond to specific construction conditions and constraint changes, providing more targeted and reliable support for construction safety management decisions.

[0154] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A knowledge graph-based highway construction safety risk assessment system, characterized in that, Includes the following steps: The multi-source construction data acquisition module is used to acquire multi-source construction data involving safety risks during highway construction, and record the corresponding time and spatial location identifiers to form a set of original construction safety data. The risk status mapping module is used to map raw construction safety data into a set of construction safety risk statuses. The construction safety knowledge graph module is used to build a knowledge graph in the field of highway construction safety. The semi-order risk state space construction module is used to determine the reachable construction safety risk state subspace in the construction safety semi-order risk state space under the current construction conditions. The reachability risk state analysis module is used to perform state reachability analysis based on the construction event sequence to determine the reachable construction safety risk state subspace. The Counterfactual Semi-Order Risk Space Reconstruction Module is used to perform counterfactual stripping processing within the reachable construction safety risk state subspace and reconstruct the counterfactual semi-order risk state space. The semi-order structural fracture identification module is used to identify whether structural fracture occurs under counterfactual conditions in the construction safety semi-order risk state space. The instability state determination module is used to determine whether the construction safety risk has entered an unavoidable instability state in the structure when there is a semi-sequence structural fracture phenomenon and there is no reachable path to retreat to a state with minimal risk of safety, and outputs the risk determination result.

2. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The risk status mapping module includes: Based on the original set of construction safety data, time alignment processing is performed on the multi-source construction data according to a unified time identifier. The multi-source construction data includes construction procedure data, traffic organization data, equipment configuration data, personnel operation data, and environmental condition data, to obtain the construction procedure status, traffic organization status, equipment operation status, personnel operation status, and environmental condition status that correspond one-to-one with each time identifier. Under the same time identifier, the construction process status, traffic organization status, equipment operation status, personnel operation status and environmental condition status are associated based on the spatial location identifier. Based on the status correspondence between the statuses, the construction status is mapped to the risk status, and each type of construction status is mapped to the corresponding component in the construction safety risk status vector. Combine the components corresponding to the same time identifier and the same spatial location identifier to generate a construction safety risk status vector corresponding to the time identifier and spatial location identifier. The construction safety risk status vectors corresponding to different time markers and different spatial location markers are aggregated to form a construction safety risk status set.

3. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The construction safety knowledge graph module includes: Based on the original construction safety data set, entity recognition processing is performed on the multi-source construction data involved in the highway construction process to determine the construction element entities. Entity recognition processing is also performed on the data related to construction safety risks to determine the construction risk entities. Corresponding entity identifiers are generated for each construction element entity and each construction risk entity. Based on the sequential and dependent relationships of construction procedures in the construction process, procedure constraint relationships are established between construction element entities, and the procedure constraint relationships are associated with the corresponding construction element entities; Based on the correspondence between construction element entities and construction risk entities in terms of spatial location identification, a spatial constraint relationship is constructed between construction element entities and construction risk entities, and the spatial constraint relationship is associated with the corresponding construction element entities and construction risk entities. Based on the correspondence between construction element entities and construction risk entities in terms of time identifiers, a time constraint relationship is constructed between construction element entities and construction risk entities, and the time constraint relationship is associated with the corresponding construction element entities and construction risk entities. Based on the safety control conditions formed during the construction safety management process, a safety constraint relationship is established between the construction element entity and the construction risk entity, and the safety constraint relationship is associated with the corresponding construction element entity and construction risk entity; By unifying the organization of construction element entities, construction risk entities, and process constraints, spatial constraints, temporal constraints, and safety constraints, a knowledge graph for the field of highway construction safety is formed.

4. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The semi-order risk state space construction module includes: Based on the set of construction safety risk states, any two construction safety risk states are selected as risk state pairs to be judged, and the construction safety risk state vectors corresponding to each construction safety risk state in the risk state pairs to be judged are obtained. For the risk status pairs to be determined, based on the knowledge graph of highway construction safety, the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship corresponding to the construction safety risk status are extracted, and the constraint relationship is organized into constraint combination; Under the constraints, based on the satisfying and covering relationship between the two construction safety risk states in the constraint combination, it is determined whether one of the construction safety risk states forms a constraint inclusion for the other construction safety risk state under the constraint combination. If the constraints of determining one construction safety risk state cover the other construction safety risk state, and there is no constraint relationship that reverses the coverage relationship, then a one-way dominance relationship is determined between the two construction safety risk states, and the one-way dominance relationship is recorded as a semi-order relationship between the construction safety risk states. For all construction safety risk states in the set of construction safety risk states, the dominance judgment process is repeatedly executed, the generated semi-order relations are collected, and a construction safety semi-order risk state space is constructed based on the semi-order relations.

5. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The reachability risk status analysis module includes: Under the current construction conditions, based on a unified time identifier, the construction safety risk state vectors corresponding to each construction safety risk state in the construction safety risk state set are arranged in chronological order, and the process of changes in the construction safety risk state vectors under adjacent time identifiers is identified as construction events, forming a construction event sequence arranged in chronological order. In the construction safety semi-sequence risk state space, the construction safety risk state corresponding to the start time identifier of the construction event sequence is selected as the initial construction safety risk state; For each construction event in the construction event sequence, in the construction safety semi-order risk state space, based on the unidirectional domination constraint defined by the semi-order relationship, it is determined whether the construction safety risk state change caused by the construction event maintains the semi-order relationship without being destroyed, and only the construction safety risk state change that maintains the semi-order relationship is retained. Based on the changes in construction safety risk status that maintain the semi-order relationship, the construction safety risk status that can be reached from the initial construction safety risk status through the construction event sequence is gradually aggregated to form a state arrival set. The set of states that can be reached is defined as the subspace of the reachable construction safety risk states under the current construction conditions.

6. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The counterfactual semi-order risk space reconstruction module includes: The reachable construction safety risk state subspace is used as the initial state range for counterfactual analysis, and the construction elements or construction events that are the objects of counterfactual analysis are determined within the initial state range. Based on the knowledge graph of highway construction safety, the construction element entity or construction risk entity corresponding to the counterfactual analysis object is located, and the process constraint relationship, spatial constraint relationship, temporal constraint relationship and safety constraint relationship directly related to the construction element entity or construction risk entity are extracted to form a set of constraint relationships to be stripped. While keeping all other construction conditions except for the counterfactual analysis object unchanged, the set of constraint relations to be stripped is subjected to counterfactual stripping processing to generate counterfactual construction conditions; Under counterfactual construction conditions, the subspace of achievable construction safety risk states is used as the only allowed set of states. Based on the constraint combination after removing constraints, the dominance relationship between construction safety risk states is re-determined to generate a semi-order relation set consistent with the counterfactual construction conditions. The semi-order relations in the original construction safety semi-order risk state space are replaced with a set of semi-order relations, and the structural relations between construction safety risk states are reorganized based on the replaced set of semi-order relations to construct the counterfactual semi-order risk state space.

7. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The semi-order structure fracture identification module includes: The reachable construction safety risk state subspace is used as the sole scope of the semi-order structure determination. Within this scope, based on the construction safety semi-order risk state space, the set of minimal risk states that are not dominated by any other construction safety risk state under the semi-order relation constraint is identified. Within the defined scope of the reachable construction safety risk state subspace, based on the counterfactual semi-order risk state space, for each construction safety risk state in the reachable construction safety risk state subspace, it is determined whether it can still form a lower bound constraint relationship with at least one minimal risk state under the semi-order relation constraint. When it is determined that at least one construction safety risk state can no longer form a lower bound constraint relationship with any minimal risk state in the counterfactual semi-order risk state space, it is determined that the construction safety risk state has experienced a semi-order relationship dominance connectivity failure under counterfactual conditions. In the reachable construction safety risk state subspace, if it is determined that there is at least one construction safety risk state in which a semi-order relation dominates the failure of connectivity, then the construction safety semi-order risk state space is determined to have a semi-order structure fracture phenomenon under counterfactual conditions.

8. The knowledge graph-based highway construction safety risk assessment system according to claim 1, characterized in that, The instability state determination module includes: The subspace of the achievable construction safety risk state is used as the sole scope of the judgment on the unavoidable structural instability. Within the scope of the judgment, the semi-order structural fracture phenomenon determined by the previous steps is accepted as the premise for structural judgment. Within the defined subspace of the reachable construction safety risk state, for each construction safety risk state, based on the counterfactual semi-order risk state space, under the semi-order relation constraint, it is determined whether there is still a possibility of structural regression. When it is determined that there is no possibility of structural regression in the counterfactual semi-order risk state space, it is determined that the construction safety risk state cannot be regressed to the safety minimum risk state through the semi-order relationship under counterfactual conditions. In the subspace of reachable construction safety risk states, if each construction safety risk state satisfies the condition that it cannot regress to the state of minimum safety risk through the semi-order relationship, and the semi-order structural fracture phenomenon has been confirmed, then it is determined that the construction safety risk has entered an unavoidable structural instability state, and the corresponding risk judgment result is output.

9. A knowledge graph-based highway construction safety risk assessment system according to claim 8, characterized in that, The determination of the state of minimal safety risk includes: In the constructed semi-order risk state space of construction safety, based on the established semi-order relationship, a set of candidate minimum risk states is determined for the identified minimum risk states. For each minimum risk state in the candidate minimum risk state set, the determined constraint combination corresponding to the minimum risk state is invoked to determine whether the constraint combination simultaneously meets the construction safety conditions under the current construction conditions. When it is determined that the combination of constraints meets the conditions for the establishment of construction safety, the corresponding minimum risk state is determined as the minimum risk state of safety. If any condition in the combination of constraints does not meet the conditions for the establishment of construction safety, the corresponding minimum risk state shall be excluded as the minimum risk state for safety. At least one state with minimal safety risk is identified as the safety reference state upon which the semi-order relation regression determination and the structural instability determination are based.

Images