CN108829939A - A kind of theory and method for numerical simulation for examining the skeleton stability that gathers materials - Google Patents
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Abstract
本发明公开了一种检验集料骨架稳定性的理论及数值模拟方法，包括：确定沥青混合料的材料组成、局部理论检验方法、全局理论检验方法；根据理论检验确定集料骨架筛孔范围；确定每一档集料在沥青混合料中的体积分数；确定每一档集料的投放个数、粒径调整系数，构建集料混合物的离散元仿真模型；定义集料的细观参数；确定虚拟加载方式；确定虚拟加载停止条件；输出仿真试验结果；确定构成集料骨架的关键筛孔，确定起稳定作用的关键筛孔，确定起干扰作用的关键筛孔。本发明通过局部和全局理论检验方法，实现了所述起骨架作用的筛孔范围的确定，通过集料混合物的离散元仿真试验，实现了检验集料骨架稳定性及查找干扰粒径的方法。
The invention discloses a theory and numerical simulation method for testing the stability of an aggregate skeleton, comprising: determining the material composition of an asphalt mixture, a local theoretical testing method, and a global theoretical testing method; and determining the sieve hole range of the aggregate skeleton according to the theoretical testing; Determine the volume fraction of each grade of aggregate in the asphalt mixture; determine the number and particle size adjustment coefficient of each grade of aggregate, and build a discrete element simulation model of the aggregate mixture; define the mesoscopic parameters of the aggregate; determine Virtual loading method; determine virtual loading stop conditions; output simulation test results; determine the key sieve holes that constitute the aggregate skeleton, determine the key sieve holes that play a stabilizing role, and determine the key sieve holes that play a disturbing role. The invention realizes the determination of the sieve hole range which acts as a skeleton through local and global theoretical testing methods, and realizes the method of checking the stability of the aggregate skeleton and finding the interference particle size through the discrete element simulation test of the aggregate mixture.
Description
技术领域technical field
本发明涉及一种集料骨架稳定性理论检验和集料混合物离散元仿真技术，特别涉及一种检验集料骨架稳定性的理论及数值模拟方法，是基于三维离散单元法的集料混合物骨架稳定性检验方法，属于道路工程技术领域。。The invention relates to a theoretical test of the stability of aggregate skeleton and a discrete element simulation technology of aggregate mixture, in particular to a theory and numerical simulation method for testing the stability of aggregate skeleton, which is based on the three-dimensional discrete element method for the stability of the skeleton of aggregate mixture. The test method belongs to the technical field of road engineering. .
背景技术Background technique
要检验集料混合物在沥青混合料中的骨架稳定性，首先需要获取沥青混合料的材料组成和材料性质，在已知集料级配、沥青含量、空隙率、有效沥青的含量、被集料吸收的沥青含量、沥青的密度、沥青混合料的密度、集料的密度条件下建立局部及全局理论检验方法。如果上述条件已知，即可根据材料组成计算每一档集料的投放个数，建立集料混合物虚拟试件进行三维尺度的集料混合物压缩试验。To test the skeleton stability of the aggregate mixture in the asphalt mixture, it is first necessary to obtain the material composition and material properties of the asphalt mixture. Local and global theoretical test methods are established under the conditions of absorbed asphalt content, asphalt density, asphalt mixture density, and aggregate density. If the above conditions are known, the number of aggregates in each grade can be calculated according to the material composition, and a virtual specimen of the aggregate mixture can be established to conduct a three-dimensional aggregate mixture compression test.
要知道室内试验和现场试验并不能直观地检验集料级配的稳定性，无法知道不同筛孔的集料对集料骨架的贡献率大小，基本只能通过沥青混合料在各种温度下表现出的宏观性能来间接评价集料骨架稳定性，这样既耗时又增加成本，试验得到的评价结果也并不理想。It is necessary to know that indoor tests and field tests cannot visually test the stability of aggregate gradation, and it is impossible to know the contribution rate of aggregates with different sieve holes to the aggregate skeleton. It is time-consuming and cost-intensive to indirectly evaluate the stability of the aggregate skeleton based on the obtained macroscopic properties, and the evaluation results obtained from the test are not ideal.
然而，通过集料混合物虚拟压缩试验可以直观的检验集料骨架的稳定性，并能统计不同粒径的集料对集料骨架的贡献率大小。However, through the aggregate mixture virtual compression test, the stability of the aggregate skeleton can be visually inspected, and the contribution rate of aggregates with different particle sizes to the aggregate skeleton can be counted.
发明内容Contents of the invention
本发明所要解决的技术问题是提供一种检验集料骨架稳定性的理论及数值模拟方法，该方法是一种在已知集料级配、沥青含量、空隙率、有效沥青的含量、被集料吸收的沥青含量、沥青的密度、沥青混合料的密度、集料的密度条件下的理论及数值模拟检验方法，根据局部和全局理论检验方法能够得到构成集料骨架的筛孔范围，确定集料骨架范围以外的物质对骨架的干扰作用，根据集料混合物压缩试验，能够快速准确地得到此种级配下构成集料骨架的关键筛孔，起稳定作用的关键筛孔，起干扰作用的关键筛孔，以解决目前室内试验及现场试验高成本、耗时以及试验结果不直观、波动性的问题。The technical problem to be solved by the present invention is to provide a theoretical and numerical simulation method for testing the stability of the aggregate skeleton. According to the theoretical and numerical simulation test methods under the conditions of asphalt content absorbed by the material, asphalt density, asphalt mixture density, and aggregate density, the range of sieve holes constituting the aggregate skeleton can be obtained according to the local and global theoretical test methods, and the set According to the aggregate mixture compression test, it is possible to quickly and accurately obtain the key sieve holes that constitute the aggregate skeleton under this gradation, the key sieve holes that play a stabilizing role, and the key sieve holes that play a disturbing role. Key sieve holes to solve the problems of high cost, time-consuming, unintuitive and volatile test results in current indoor and field tests.
本发明为解决上述技术问题采用以下技术方案：The present invention adopts the following technical solutions for solving the problems of the technologies described above:
本发明提供一种检验集料骨架稳定性的理论及数值模拟方法，包括如下步骤：The invention provides a theoretical and numerical simulation method for testing the stability of the aggregate skeleton, comprising the following steps:
(1)确定沥青混合料的材料组成：首先确定沥青混合料的材料组成和材料性质，再根据材料性质确定计算检验参数所需的基础参数；(1) Determine the material composition of the asphalt mixture: first determine the material composition and material properties of the asphalt mixture, and then determine the basic parameters required to calculate the inspection parameters according to the material properties;
(2)确定局部理论检验方法：根据相邻筛孔之间的颗粒保持接触的状态定义局部理论检验方法，并定义局部检验参数；(2) Determine the local theoretical test method: define the local theoretical test method according to the state that the particles between adjacent sieve holes are kept in contact, and define the local test parameters;
(3)确定全局理论检验方法：根据构成集料骨架范围以外的物质对集料骨架的干扰程度定义全局理论检验方法，并定义全局检验参数；(3) Determine the global theoretical test method: define the global theoretical test method according to the degree of interference to the aggregate skeleton by the substances outside the scope of the aggregate skeleton, and define the global test parameters;
(4)根据理论检验确定集料骨架筛孔范围：根据局部和全局理论检验方法以及检验参数确定构成集料骨架的筛孔范围，确定集料骨架范围以外的物质对骨架的干扰作用；(4) Determine the sieve hole range of the aggregate skeleton according to the theoretical test: determine the sieve hole range that constitutes the aggregate skeleton according to the local and global theoretical test methods and test parameters, and determine the interference effect of the substances outside the aggregate skeleton range on the skeleton;
(5)确定每一档集料的投放个数：根据沥青混合料的材料组成和材料性质确定集料混合物在沥青混合料中的体积分数，结合每一档集料的通过率确定每一档集料在沥青混合料中的体积分数；根据每一档集料在沥青混合料中的体积分数、集料混合物在沥青混合料中的体积分数以及每一档集料的平均粒径确定每一档集料的投放个数；(5) Determining the number of aggregates in each grade: determine the volume fraction of the aggregate mixture in the asphalt mixture according to the material composition and material properties of the asphalt mixture, and determine each grade in combination with the passing rate of each grade of aggregate The volume fraction of aggregate in asphalt mixture; according to the volume fraction of each grade of aggregate in asphalt mixture, the volume fraction of aggregate mixture in asphalt mixture and the average particle size of each grade of aggregate to determine each The number of feed aggregates;
(6)构建集料混合物的离散元仿真模型：确定虚拟试件尺寸和加载速率，建立固定边界条件，确定每一档集料粒径调整系数，确定集料的细观参数，建立集料混合物离散元仿真模型；(6) Construct the discrete element simulation model of the aggregate mixture: determine the size and loading rate of the virtual specimen, establish fixed boundary conditions, determine the adjustment coefficient of each aggregate particle size, determine the mesoscopic parameters of the aggregate, and establish the aggregate mixture Discrete element simulation model;
(7)确定虚拟加载方式：根据集料混合物投放后的状态，确定虚拟加载方式三种状态，其中，三种状态依次为自然堆积、预加载以及正式加载；(7) Determine the virtual loading method: according to the state of the aggregate mixture, determine the three states of the virtual loading method, wherein the three states are natural accumulation, preloading and formal loading;
(8)确定虚拟加载停止条件：根据集料混合物的压碎值试验确定集料开始产生破坏的最大荷载作为第一个虚拟加载停止条件，为防止集料混合物结构重组要求最大应变达到0.2作为第二个虚拟加载停止条件；(8) Determine the virtual loading stop condition: According to the crushing value test of the aggregate mixture, determine the maximum load at which the aggregate begins to fail as the first virtual loading stop condition. In order to prevent the structural reorganization of the aggregate mixture, the maximum strain of 0.2 is required as the second Two dummy loading stop conditions;
(9)输出仿真试验结果：当虚拟加载停止后，输出仿真试验结果，其中，仿真试验结果包括虚拟加载板力-位移曲线、每档集料每个接触处的接触力、每档集料的接触数量、每档集料的投放个数；(9) Output simulation test results: when the virtual loading stops, output the simulation test results, wherein the simulation test results include the force-displacement curve of the virtual loading plate, the contact force of each contact point of each aggregate, and the contact force of each aggregate. The number of contacts and the number of aggregates placed in each file;
(10)确定构成集料骨架的关键筛孔：定义起集料骨架作用的颗粒至少存在一个接触点的接触力大于集料混合物的平均接触力，定义每档集料中起骨架作用的接触点为每档集料中接触处的接触力大于平均接触力的接触点，定义每档集料对集料骨架的贡献为每档集料起骨架作用的接触点的接触力的和除以所有档集料起骨架作用的接触点的接触力的和；根据步骤(9)中输出的仿真结果统计每档集料对集料骨架的贡献，绘制集料筛孔与相应筛孔的集料对集料骨架的贡献的曲线图，定义如果处于波峰的任两档集料对集料骨架的贡献的和超过50％即为构成集料骨架的关键筛孔；(10) Determine the key sieve openings that constitute the aggregate skeleton: define that the particles that act as the aggregate skeleton have at least one contact point where the contact force is greater than the average contact force of the aggregate mixture, and define the contact point that acts as a skeleton in each aggregate For each level of aggregates, the contact force at the contact point is greater than the average contact force, and the contribution of each level of aggregate to the aggregate skeleton is defined as the sum of the contact forces of the contact points where each level of aggregate acts as a skeleton divided by all levels The sum of the contact forces of the contact points where the aggregate acts as a skeleton; according to the simulation results output in step (9), the contribution of each aggregate to the aggregate skeleton is counted, and the aggregate pairs of aggregate sieve holes and corresponding sieve holes are drawn. The curve diagram of the contribution of the aggregate skeleton defines that if the sum of the contribution of any two aggregates at the peak to the aggregate skeleton exceeds 50%, it is the key sieve hole that constitutes the aggregate skeleton;
(11)确定起稳定作用的关键筛孔：定义起稳定骨架作用的颗粒其接触点的接触力应小于集料混合物的平均接触力，定义每档集料中起稳定作用的接触点为每档集料中接触处的接触力小于平均接触力的接触点，定义每档集料对稳定集料骨架的贡献为每档集料起稳定作用的接触点的接触力的和除以所有档集料起稳定作用的接触点的接触力的和；统计每档集料对稳定集料骨架的贡献，绘制集料筛孔与相应筛孔的集料对稳定集料骨架的贡献的曲线图，定义如果处于波峰的任两档集料对稳定集料骨架的贡献的和超过50％即为起稳定作用的关键筛孔；(11) Determine the key sieve hole that plays a stabilizing role: define the contact force at the contact point of the particles that stabilize the skeleton should be less than the average contact force of the aggregate mixture, define the contact point that plays a stabilizing role in each grade of aggregate as each grade The contact force at the contact point in the aggregate is less than the average contact force, and the contribution of each level of aggregate to the stable aggregate skeleton is defined as the sum of the contact forces of the contact points that each level of aggregate plays a stabilizing role divided by all the level of aggregates The sum of the contact force of the contact point that plays a stabilizing role; the contribution of each aggregate to the stable aggregate skeleton is counted, and the contribution curve of the aggregate sieve hole and the aggregate of the corresponding sieve hole to the stable aggregate skeleton is drawn, and the definition if The sum of the contributions of any two grades of aggregates at the peak to the stable aggregate skeleton exceeds 50%, which is the key sieve opening for stabilization;
(12)确定起干扰作用的关键筛孔：根据步骤(11)中绘制的集料筛孔与相应筛孔的集料对稳定集料骨架的贡献的曲线图，定义与波峰相邻处有异常凸起的地方对应的筛孔粒径为起干扰作用的关键筛孔。(12) Determine the key sieve hole that interferes: according to the graph of the contribution of the aggregate sieve hole and the corresponding sieve hole aggregate to the stable aggregate skeleton drawn in step (11), it is defined that there is an abnormality adjacent to the wave peak The sieve hole particle size corresponding to the raised place is the key sieve hole that plays an interfering role.
作为本发明的进一步技术方案，所述步骤(1)中，确定沥青混合料的材料组成和材料性质具体包括：沥青总含量Wb，有效沥青的含量被集料吸收的沥青含量空隙率Vv，沥青的密度ρb，沥青混合料的表观密度ρm，集料的密度ρa，沥青混合料试件体积VT以及第i档集料的通过率Pa(i)，其中，第i＝1档粒径为最大一档集料粒径，随i增加集料粒径减小；As a further technical solution of the present invention, in the step (1), determining the material composition and material properties of the asphalt mixture specifically includes: the total content of asphalt W b , the content of effective asphalt Bitumen content absorbed by the aggregate Void ratio V v , density of asphalt ρ b , apparent density of asphalt mixture ρ m , density of aggregate ρ a , volume of asphalt mixture V T and passing rate of the i-th aggregate aggregate P a (i) , wherein, the particle size of the i=1st file is the maximum particle size of the first file, and the particle size of the aggregate decreases with the increase of i;
根据材料性质确定计算检验参数所需的基础参数具体包括：第i档集料的体积分数第i档集料的平均粒径被集料吸收的沥青的体积有效沥青的体积集料混合物的总体积Vat以及集料混合物占沥青混合料试件的体积分数其中， Di-1为第i-1档筛孔的粒径，Di为第i档筛孔的粒径。Determine the basic parameters needed to calculate the inspection parameters according to the material properties, specifically include: the volume fraction of the i-th file aggregate The average particle size of the i-th file aggregate volume of bitumen absorbed by the aggregate effective bitumen volume The total volume V at of the aggregate mixture and the volume fraction of the aggregate mixture in the asphalt mixture specimen in, D i-1 is the particle size of the i-1 sieve, and D i is the particle size of the i sieve.
作为本发明的进一步技术方案，所述步骤(2)中，确定局部理论检验方法具体为：符合构成集料骨架的筛孔必须满足相邻筛孔之间的颗粒必须保持接触的状态，其极限状态分为紧密接触和松弛接触两种状态，紧密接触定义为相邻两档集料中筛孔较大的那一档集料颗粒之间保持相互接触、较小的那一档集料填充较大一档集料的空隙，松弛接触定义为相邻两档集料中筛孔较大的那一档集料颗粒与较小的那一档集料颗粒之间保持相互接触；As a further technical solution of the present invention, in the step (2), the local theoretical testing method is specifically determined as follows: the sieve holes constituting the aggregate skeleton must meet the state that the particles between adjacent sieve holes must maintain contact, and the limit The state is divided into two states: close contact and loose contact. Close contact is defined as the aggregate particles of the larger sieve of the adjacent two aggregates keep in contact with each other, and the smaller aggregate is filled more closely. The gap between the aggregates of the first grade, the loose contact is defined as the aggregate particles of the larger grade and the smaller aggregate particles keep in contact with each other in the two adjacent grades of aggregates;
第i档集料的局部理论检验参数包括第i档和第i+1档集料的加权平均粒径和第i档集料占第i档和第i+1档两档集料的体积分数其中， The local theoretical test parameters of the i-th aggregate include the weighted average particle size of the i-th aggregate and the i+1 aggregate The volume fraction of the i-th file aggregate and the i-th file and the i+1 file in,
如果第i档集料的局部理论检验参数满足局部理论检验公式和即表示此档集料满足局部理论检验；根据局部理论检验公式对第一档至最后一档集料依次进行检验，从而确定构成集料骨架的筛孔范围。If the local theoretical test parameters of the i-th aggregate meet the local theoretical test formula and It means that the aggregates of this file meet the local theoretical test; according to the local theoretical test formula, the first to the last aggregates are tested in turn, so as to determine the range of sieve holes that constitute the aggregate skeleton.
作为本发明的进一步技术方案，所述步骤(3)中，确定全局理论检验方法具体是：全局理论检验方法定义为由集料骨架形成的空隙能被介质成分填充且不形成干扰，其表达式为干扰因素定义为介质成分对集料骨架的干扰程度DF，其中， 为步骤(2)中得到的构成集料骨架的筛孔范围集料形成的空隙的体积，Va SS为小于构成集料骨架最小筛孔的集料总体积，为小于构成集料骨架最小筛孔的细集料被吸收的沥青的体积。As a further technical solution of the present invention, in the step (3), the determination of the global theory test method is specifically: the global theory test method is defined as the gap formed by the aggregate skeleton can be filled by the medium components without interference, its expression for The interference factor is defined as the interference degree D F of the medium composition to the aggregate skeleton, where, Be the volume of the void formed by the sieve hole range aggregates that constitute the aggregate skeleton obtained in step (2), V a SS is the total volume of the aggregate that is less than the minimum sieve aperture that constitutes the aggregate skeleton, It is the volume of asphalt absorbed by fine aggregates smaller than the smallest sieve opening of the aggregate skeleton.
作为本发明的进一步技术方案，所述步骤(5)中，第i档集料的投放个数其中，第i档集料在沥青混合料中的体积分数 As a further technical solution of the present invention, in the step (5), the number of throwing of the i-th file aggregate Among them, the volume fraction of the i-th grade aggregate in the asphalt mixture
作为本发明的进一步技术方案，所述步骤(6)中，构建集料混合物的离散元仿真模型具体是：根据公路工程沥青及沥青混合料试验规程中沥青混合料压缩试验确定虚拟试件尺寸和加载速率，建立固定边界条件，在虚拟试件中根据步骤(5)计算得到的每一档集料的投放个数将每一档集料以随机分布的形式投放，根据集料的宏观性质和细观与宏观的换算公式定义集料的细观参数，并根据投放后的体积等于实际的体积确定第i档粒径调整系数Af(i)，采用粒径调整系数缩放每一档集料的粒径，建立集料混合物离散元仿真模型；其中，Af(i)的计算公式为Vk(i)为第i档集料中第k个集料的体积。As a further technical solution of the present invention, in said step (6), the discrete element simulation model of constructing the aggregate mixture is specifically: according to the asphalt mixture compression test in the highway engineering asphalt and asphalt mixture test regulations, determine the virtual specimen size and Loading rate, establish fixed boundary conditions, put each batch of aggregates in the form of random distribution according to the number of each batch of aggregates calculated in step (5) in the virtual test piece, according to the macroscopic properties of aggregates and The mesoscopic and macroscopic conversion formula defines the mesoscopic parameters of the aggregate, and determines the particle size adjustment coefficient A f (i) of the i-th file according to the volume after delivery is equal to the actual volume, and uses the particle size adjustment factor to scale each file. The particle size of the aggregate mixture is established, and the discrete element simulation model of the aggregate mixture is established; the calculation formula of A f (i) is V k (i) is the volume of the kth aggregate in the i-th aggregate.
作为本发明的进一步技术方案，所述步骤(10)中，第i档集料对集料骨架的贡献其中，整个集料混合物的平均接触力Fij为第i档集料中第j个接触点处的接触力，m为筛孔总档数。As a further technical solution of the present invention, in the step (10), the contribution of the i-th file aggregate to the aggregate skeleton where the average contact force for the entire aggregate mixture F ij is the contact force at the jth contact point in the i-th aggregate, and m is the total number of sieve holes.
作为本发明的进一步技术方案，所述步骤(11)中，第i档集料对稳定集料骨架的贡献其中，整个集料混合物的平均接触力Fij为第i档集料中第j个接触点处的接触力，m为筛孔总档数。As a further technical solution of the present invention, in the step (11), the contribution of the i-th file aggregate to the stable aggregate skeleton where the average contact force for the entire aggregate mixture F ij is the contact force at the jth contact point in the i-th aggregate, and m is the total number of sieve holes.
作为本发明的进一步技术方案，步骤(10)和(11)中绘制集料筛孔横坐标与相应筛孔的集料对集料骨架的贡献的曲线图。As a further technical solution of the present invention, in steps (10) and (11), draw a graph of the abscissa of the aggregate sieve hole and the contribution of the aggregate of the corresponding sieve hole to the aggregate skeleton.
本发明采用以上技术方案与现有技术相比，具有以下技术效果：本发明提供的集料骨架稳定性局部及全局理论检验方法，通过定义局部和全局理论检验方法和检验参数，可以确定多种级配构成集料骨架的筛孔范围，确定集料骨架范围以外的物质对骨架的干扰作用；通过集料混合物的虚拟压缩试验，可以模拟多种级配、多种沥青用量、多中空隙率状态下的集料混合物骨架稳定性，可以直观地确定构成集料骨架的关键筛孔，起稳定作用的关键筛孔，起干扰作用的关键筛孔，可以知道每一档集料对集料骨架稳定性的贡献率。Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects: the local and global theoretical testing method of aggregate skeleton stability provided by the present invention can determine various Grading constitutes the range of sieve holes of the aggregate skeleton, and determines the interference effect of substances outside the range of the aggregate skeleton on the skeleton; through the virtual compression test of the aggregate mixture, it is possible to simulate various gradations, various asphalt dosages, and multiple void ratios The stability of the skeleton of the aggregate mixture under the state can intuitively determine the key sieve holes that constitute the aggregate skeleton, the key sieve holes that play a stabilizing role, and the key sieve holes that play a disturbing role. contribution to stability.
附图说明Description of drawings
图1是本发明方法的流程图。Figure 1 is a flow chart of the method of the present invention.
具体实施方式Detailed ways
下面结合附图对本发明的技术方案做进一步的详细说明：Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
如图1所示，一种检验集料骨架稳定性的理论及数值模拟方法，包括如下步骤：As shown in Figure 1, a theoretical and numerical simulation method for testing the stability of the aggregate skeleton includes the following steps:
(一)确定沥青混合料的材料组成和材料性质：包括沥青总含量(Wb)，有效沥青的含量被集料吸收的沥青含量空隙率(Vv)，沥青的密度(ρb)，沥青混合料的表观密度(ρm)，集料的密度(ρa)，沥青混合料试件体积(VT)以及第i档集料的通过率(Pa(i))，其中，第i＝1档粒径为最大一档集料粒径，随i增加集料粒径减小。(1) Determine the material composition and material properties of the asphalt mixture: including the total content of asphalt (W b ), the content of effective asphalt Bitumen content absorbed by the aggregate Void ratio (V v ), density of asphalt (ρ b ), apparent density of asphalt mixture (ρ m ), density of aggregate (ρ a ), volume of asphalt mixture specimen (V T ) and file i Aggregate passing rate (P a (i)), wherein, the particle size of the i=1st file is the largest aggregate particle size, and the aggregate particle size decreases with the increase of i.
根据材料性质确定计算检验参数所需的基础参数具体包括：第i档集料的体积分数第i档集料的平均粒径被集料吸收的沥青的体积有效沥青的体积集料混合物的总体积(Vat)，集料混合物占沥青混合料试件的体积分数计算公式如下：Determine the basic parameters needed to calculate the inspection parameters according to the material properties, specifically include: the volume fraction of the i-th file aggregate The average particle size of the i-th file aggregate volume of bitumen absorbed by the aggregate effective bitumen volume The total volume of the aggregate mixture (V at ), the volume fraction of the aggregate mixture in the asphalt mixture specimen Calculated as follows:
式中，Di-1为第i-1档筛孔的粒径，Di为第i档筛孔的粒径。In the formula, D i-1 is the particle size of the i-1 sieve hole, and D i is the particle size of the i-th sieve hole.
(二)确定局部理论检验方法：(2) Determine the local theory test method:
符合构成集料骨架的筛孔必须满足相邻筛孔之间的颗粒必须保持接触的状态，其极限状态分为紧密接触和松弛接触两种状态，紧密接触定义为相邻两档集料中筛孔较大的那一档集料颗粒之间保持相互接触，较小的那一档集料填充较大一档集料的空隙，松弛接触定义为相邻两档集料中筛孔较大的那一档集料颗粒与较小的那一档集料颗粒之间保持相互接触。The sieve holes that constitute the aggregate skeleton must meet the state that the particles between adjacent sieve holes must maintain contact. The limit state is divided into two states: close contact and loose contact. Close contact is defined as the sieve in the adjacent two gears The particles of the aggregate with larger holes keep in contact with each other, and the smaller aggregate fills the gaps of the larger aggregate. The loose contact is defined as the mesh with the larger sieve hole in the two adjacent aggregates. That level of aggregate particles maintains mutual contact with the smaller level of aggregate particles.
第i档集料的局部理论检验参数包括第i档和第i+1档集料的加权平均粒径和第i档集料占第i档和第i+1档两档集料的体积分数计算公式分别为公式(7)和(8)：The local theoretical test parameters of the i-th aggregate include the weighted average particle size of the i-th aggregate and the i+1 aggregate The volume fraction of the i-th file aggregate and the i-th file and the i+1 file The calculation formulas are formulas (7) and (8) respectively:
如果第i档集料的局部理论检验参数满足在紧密接触状态和松弛接触状态之间(包括紧密和松弛状态)，即表示此档集料满足局部理论检验，检验公式为公式(9)和(10)：If the local theoretical test parameters of the i-th aggregate are between the tight contact state and the relaxed contact state (including tight and relaxed states), it means that the aggregate of this file satisfies the local theoretical test, and the test formula is formula (9) and ( 10):
根据局部理论检验公式对第一档开始到最后一档结束进行依次检验，确定可以构成集料骨架的筛孔范围。According to the local theoretical test formula, sequential inspections are carried out from the beginning of the first gear to the end of the last gear to determine the range of sieve holes that can form the aggregate skeleton.
(三)确定全局理论检验方法：(3) Determine the global theory testing method:
根据局部理论检验方法得到可以构成集料骨架的筛孔范围，计算出此筛孔范围内的集料形成的空隙的体积计算出小于构成集料骨架最小筛孔的集料总体积Va SS和被吸收的沥青的体积 According to the local theoretical test method, the sieve hole range that can constitute the aggregate skeleton is obtained, and the volume of the void formed by the aggregate within the sieve hole range is calculated. Calculate the total aggregate volume V a SS and the volume of absorbed bitumen smaller than the smallest sieve hole constituting the aggregate skeleton
全局理论检验方法定义为由集料主骨架形成的空隙能被介质成分填充且不形成干扰，其表达式见公式(11)；干扰因素定义为介质成分对集料骨架的干扰程度(DF)，计算公式见公式(12)。The global theoretical test method is defined as the void formed by the main aggregate skeleton can be filled by the medium components without interference, and its expression is shown in formula (11); the interference factor is defined as the degree of interference of the medium components on the aggregate skeleton (D F ) , see the formula (12) for the calculation formula.
(四)根据理论检验确定集料骨架筛孔范围：根据局部和全局理论检验方法和检验参数确定构成集料骨架的筛孔范围，确定集料骨架范围以外的物质对骨架的干扰作用。(4) Determine the sieve hole range of the aggregate skeleton according to the theoretical test: determine the sieve hole range that constitutes the aggregate skeleton according to the local and global theoretical test methods and test parameters, and determine the interference of substances outside the range of the aggregate skeleton on the skeleton.
(五)确定每一档集料的投放个数：根据第i档集料的体积分数与集料混合物占沥青混合料试件的体积分数计算第i档集料在沥青混合料中的体积分数计算公式为式(13)；然后根据第i档集料在沥青混合料中的体积分数第i档集料的平均粒径以及沥青混合料试件体积(VT)确定第i档集料的投放个数(Ni)，计算公式为式(14)。(5) Determine the number of aggregates to be placed in each file: according to the volume fraction of the i-th file aggregate The volume fraction of asphalt mixture specimen mixed with aggregate Calculate the volume fraction of the i-th file aggregate in the asphalt mixture The calculation formula is formula (13); then according to the volume fraction of the i-th grade aggregate in the asphalt mixture The average particle size of the i-th file aggregate And the volume of the asphalt mixture specimen (V T ) determines the number of aggregates in the i-th file (N i ), and the calculation formula is formula (14).
(六)构建集料混合物的离散元仿真模型：根据JTG E20-2011公路工程沥青及沥青混合料试验规程中沥青混合料单轴压缩试验确定虚拟试件尺寸和加载速率，由于集料为无粘结的散体混合物，在加载时应建立固定边界条件，在虚拟试件中随机投放上一步计算得到的每一档集料的个数，根据集料的宏观性质和细观与宏观的换算公式定义集料的细观参数，并根据投放后的体积等于实际的体积确定第i档粒径调整系数(Af(i))(计算公式为公式(15))，采用粒径调整系数缩放每一档集料的粒径，建立更接近实际状态的集料混合物离散元仿真模型。(6) Construct the discrete element simulation model of the aggregate mixture: According to the uniaxial compression test of the asphalt mixture in the JTG E20-2011 road engineering asphalt and asphalt mixture test regulations, determine the virtual specimen size and loading rate, because the aggregate is inviscid For the bulk mixture of knots, fixed boundary conditions should be established when loading, and the number of each grade of aggregate calculated in the previous step is randomly placed in the virtual test piece. According to the macroscopic properties of the aggregate and the conversion formula of mesoscopic and macroscopic Define the mesoscopic parameters of the aggregate, and determine the i-th grade particle size adjustment coefficient (A f (i)) according to the volume after delivery is equal to the actual volume (the calculation formula is formula (15)), and use the particle size adjustment coefficient to scale each The particle size of aggregates in the first file is used to establish a discrete element simulation model of aggregate mixture that is closer to the actual state.
(七)确定虚拟加载方式：根据集料混合物投放后的状态，确定虚拟加载方式三种状态依次为自然堆积、预加载以及正式加载。(7) Determine the virtual loading method: According to the state of the aggregate mixture after being put in, determine the three states of the virtual loading method as natural accumulation, preloading and formal loading.
(八)确定虚拟加载停止条件：根据集料混合物的压碎值试验确定集料开始产生破坏的最大荷载作为第一个虚拟加载停止条件，为防止集料混合物结构重组要求最大应变达到0.2作为第二个虚拟加载停止条件。(8) Determine the virtual loading stop condition: According to the crushing value test of the aggregate mixture, determine the maximum load at which the aggregate begins to fail as the first virtual loading stop condition. In order to prevent the structural reorganization of the aggregate mixture, the maximum strain required to reach 0.2 is used as the second Two dummy loading stop conditions.
(九)输出仿真试验结果：当虚拟加载停止后，输出仿真试验结果包括虚拟加载板力-位移曲线，每档集料每个接触处的接触力，每档集料的接触数量，每档集料的投放个数。(9) Output simulation test results: When the virtual loading stops, the output simulation test results include the force-displacement curve of the virtual loading plate, the contact force at each contact point of each aggregate, the contact quantity of each aggregate, and the contact force of each aggregate. The number of feeding materials.
(十)确定构成集料骨架的关键筛孔：(10) Determine the key sieve holes that constitute the aggregate skeleton:
提取第i档集料的接触力和第i档集料的个数(Ni)，计算整个集料混合物的平均接触力(Ftavg)，计算公式为(16)。Extract the contact force of the i-th file aggregate and the number of aggregates in the i-th file (N i ), calculate the average contact force (F tavg ) of the entire aggregate mixture, and the calculation formula is (16).
定义起集料骨架作用的颗粒至少存在一个接触点的接触力大于集料混合物的平均接触力，定义第i档集料中起骨架作用的接触点为第i档集料中接触处的接触力大于平均接触力的接触点，定义第i档集料对集料骨架的贡献fti＞tavg为每档集料起骨架作用的接触点的接触力的和除以所有档集料起骨架作用的接触点的接触力的和，其计算公式为(17)。It is defined that there is at least one contact point of the particle that acts as the aggregate skeleton, and the contact force is greater than the average contact force of the aggregate mixture, and the contact point that acts as a skeleton in the i-th aggregate is defined as the contact force at the contact point in the i-th aggregate For contact points that are greater than the average contact force, define the contribution of the i-th aggregate to the aggregate skeleton f ti>tavg is the sum of the contact forces at the contact points where each aggregate acts as a skeleton divided by the skeleton effect of all aggregates The sum of the contact force at the contact point is calculated as (17).
根据步骤(九)中输出的仿真结果统计每档集料对集料骨架的贡献，绘制集料筛孔(横坐标)与相应筛孔的集料对集料骨架的贡献的曲线图，定义如果处于波峰的任两档集料对集料骨架的贡献的和超过50％即为构成集料骨架的关键筛孔。According to the simulation results output in step (9), the contribution of each grade of aggregate to the aggregate skeleton is counted, and the graph of the contribution of the aggregate sieve hole (abscissa) and the aggregate of the corresponding sieve hole to the aggregate skeleton is drawn, and if The sum of the contributions of any two grades of aggregates at the peak to the aggregate skeleton exceeds 50%, which is the key sieve hole that constitutes the aggregate skeleton.
式中，Fij为第i档集料中第j个接触点处的接触力，m为总档数。In the formula, F ij is the contact force at the jth contact point in the i-th aggregate, and m is the total number of files.
(十一)确定起稳定作用的关键筛孔：(11) Determine the key sieve holes that play a stabilizing role:
定义起稳定骨架作用的颗粒其接触点的接触力应小于集料混合物的平均接触力，定义第i档集料中起稳定作用的接触点为第i档集料中接触处的接触力小于平均接触力的接触点，定义第i档集料对稳定集料骨架的贡献fti≤tavg为第i档集料起稳定作用的接触点的接触力的和除以所有档集料起稳定作用的接触点的接触力的和，计算公式为公式(18)。It is defined that the contact force at the contact point of the particles that stabilize the skeleton should be less than the average contact force of the aggregate mixture, and the contact point that plays a stabilizing role in the i-th aggregate is defined as the contact force at the contact point in the i-th aggregate is less than the average The contact point of the contact force, defining the contribution of the i-th aggregate to the stable aggregate skeleton f ti ≤ tavg is the sum of the contact forces at the contact points where the i-th aggregate stabilizes divided by the stabilizing effect of all aggregates The sum of the contact force at the contact point is calculated as formula (18).
根据步骤(九)中输出的仿真结果统计每档集料对稳定集料骨架的贡献，绘制集料筛孔(横坐标)与相应筛孔的集料对稳定集料骨架的贡献的曲线图，定义如果处于波峰的任两档集料对稳定集料骨架的贡献的和超过50％即为起稳定作用的关键筛孔。According to the simulation result output in the step (nine), the contribution of each gear aggregate to the stable aggregate skeleton is counted, and the graph of the contribution of the aggregate of the aggregate sieve hole (abscissa) and the corresponding sieve hole to the stable aggregate skeleton is drawn, Definition If the sum of the contribution of any two grades of aggregates at the peak to the stable aggregate skeleton exceeds 50%, it is the key sieve hole that plays a stabilizing role.
(十二)确定起干扰作用的关键筛孔：(12) Determine the key sieve holes that interfere:
根据步骤(十一)中绘制的集料筛孔(横坐标)与相应筛孔的集料对稳定集料骨架的贡献的曲线图，定义与波峰相邻处有异常凸起的地方对应的筛孔粒径为起干扰作用的关键筛孔。According to the graph of the aggregate sieve hole (abscissa) drawn in step (11) and the contribution of the aggregate of the corresponding sieve hole to the stable aggregate skeleton, define the sieve corresponding to the abnormally raised place adjacent to the wave peak The pore size is the key sieve opening for interference.
本发明一种检验集料骨架稳定性的理论及数值模拟方法，通过局部和全局理论检验方法，实现了所述起骨架作用的筛孔范围的确定，通过集料混合物的离散元仿真试验，实现了检验集料骨架稳定性及查找干扰粒径的方法。理论检验方法和仿真程序检验算法的可复制性和智能性较强，不限制检验级配的类型，为集料级配和沥青混合料优化设计提供了参考。The present invention is a theoretical and numerical simulation method for testing the stability of the aggregate skeleton. Through the local and global theoretical testing methods, the determination of the range of the sieve holes that play the role of the skeleton is realized. Through the discrete element simulation test of the aggregate mixture, the The method of testing the stability of aggregate skeleton and finding the interfering particle size is established. The theoretical test method and the simulation program test algorithm are highly reproducible and intelligent, and do not limit the type of test gradation, which provides a reference for the optimization design of aggregate gradation and asphalt mixture.
以上所述，仅为本发明中的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉该技术的人在本发明所揭露的技术范围内，可理解想到的变换或替换，都应涵盖在本发明的包含范围之内，因此，本发明的保护范围应该以权利要求书的保护范围为准。The above is only a specific implementation mode in the present invention, but the scope of protection of the present invention is not limited thereto. Anyone familiar with the technology can understand the conceivable transformation or replacement within the technical scope disclosed in the present invention. All should be covered within the scope of the present invention, therefore, the protection scope of the present invention should be based on the protection scope of the claims.
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