CN115221727B - A method for determining parameters of numerical simulation model of rock mass based on water content - Google Patents

A method for determining parameters of numerical simulation model of rock mass based on water content Download PDF

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CN115221727B
CN115221727B CN202210939482.1A CN202210939482A CN115221727B CN 115221727 B CN115221727 B CN 115221727B CN 202210939482 A CN202210939482 A CN 202210939482A CN 115221727 B CN115221727 B CN 115221727B
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water content
rock mass
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tunnel
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顾晓彬
赵晨阳
雷明锋
彭龙
张运波
何玉珠
肖勇卓
王路
贾朝军
吕俊
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Central South University
CCCC Third Harbor Engineering Co Ltd
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Abstract

本发明公开一种基于含水率的岩体的数值仿真模型参数确定方法,包括:节理裂隙仿真模型的生成;参数随含水率的变化关系式的获取;对岩体的参数进行标定;获取不同含水率下的岩体力学参数。本发明方法在结合室内岩石力学实验确定岩石力学特征随含水率的变化规律的基础上,采用参数标定方法得到特定含水率情况下的岩体力学参数,进一步基于岩石力学参数和岩体力学参数的映射关系确定岩体力学参数的变化关系式,从而得到不同含水率情况下的岩体数值仿真模型实现参数的计算,能够高效且高精度获得隧道的变形数据,为隧道施工安全的数值仿真分析提供指导。

The invention discloses a method for determining parameters of a numerical simulation model of rock mass based on moisture content, which includes: generation of joint and fissure simulation models; acquisition of relationship expressions of parameters changing with moisture content; calibration of parameters of rock mass; acquisition of different water contents Rock mass mechanical parameters under the rate. The method of the present invention combines indoor rock mechanics experiments to determine the changing rules of rock mechanical characteristics with water content, adopts parameter calibration methods to obtain rock mass mechanical parameters under specific water content conditions, and further calculates rock mass mechanical parameters based on rock mechanical parameters and rock mass mechanical parameters. The mapping relationship determines the changing relationship of the mechanical parameters of the rock mass, thereby obtaining the numerical simulation model of the rock mass under different water contents to calculate the parameters. It can obtain the deformation data of the tunnel with high efficiency and high precision, providing numerical simulation analysis for the safety of tunnel construction. guide.

Description

一种基于含水率的岩体的数值仿真模型参数确定方法A method for determining parameters of numerical simulation model of rock mass based on water content

技术领域Technical field

本发明涉及隧道施工技术领域,特别是涉及一种基于含水率的岩体的数值仿真模型参数确定方法。The invention relates to the technical field of tunnel construction, and in particular to a method for determining parameters of a numerical simulation model of rock mass based on moisture content.

背景技术Background technique

受复杂地质条件影响,隧道不同里程处岩体的含水率存在较大变化,如,地表降水、地下水等会沿裂隙在断层破碎带中进行渗流。对于断层破碎带周边的岩体,其含水率会因距断层破碎带距离的增加而逐渐降低。对于软质岩石,其力学性质受含水率的影响十分显著,如,较高含水率的岩石往往具有较低的强度。含水率的变化同样会导致岩石的弹性模量、粘聚力、内摩擦角发生变化。Affected by complex geological conditions, the moisture content of the rock mass at different mileage of the tunnel changes greatly. For example, surface precipitation, groundwater, etc. will seep along the cracks in the fault fracture zone. For the rock mass surrounding the fault fracture zone, its moisture content will gradually decrease as the distance from the fault fracture zone increases. For soft rocks, their mechanical properties are significantly affected by moisture content. For example, rocks with higher moisture content tend to have lower strength. Changes in moisture content will also cause changes in the rock's elastic modulus, cohesion, and internal friction angle.

隧道等地下工程施工期间,安全性一直是相关领域从业人员的关注重点。当隧道周围的岩石为软质岩石时,高含水率情况下隧道开挖施工易出现大变形问题,如出现初期支护断裂、混凝土剥落、二次衬砌开裂严重等,给施工安全带来严重挑战。既有工程经验同时表明,对于同一类型岩体,含水率较低情况下,隧道开挖并不会出现大变形问题。这说明,岩体的含水率对隧道变形的影响极其显著。During the construction of tunnels and other underground projects, safety has always been the focus of practitioners in related fields. When the rock around the tunnel is soft rock, tunnel excavation construction under high moisture content is prone to large deformation problems, such as initial support fractures, concrete spalling, severe secondary lining cracking, etc., which pose serious challenges to construction safety. . Existing engineering experience also shows that for the same type of rock mass, when the water content is low, large deformation problems will not occur during tunnel excavation. This shows that the moisture content of the rock mass has an extremely significant impact on the tunnel deformation.

隧道周围岩体为软质岩体,且其含水率可能存在较大变化时,如隧道需穿越断层破碎带,为应对可能发生的大变形风险,通常需提前制定风险应对措施,这就需要事先开展施工安全性分析。随着计算机技术的发展,数值仿真逐渐成为分析隧道施工安全性的重要手段之一。无论是采用有限元法、有限差分、离散元法、块体离散元法等多种方法中的哪一种,所建立数值仿真模型分析结果的准确性均与输入的岩体力学参数、节理面参数等密切相关。这些参数中,岩体力学参数的准确性尤为重要,主要是弹性模量、粘聚力、内摩擦角。When the rock mass around the tunnel is soft rock mass and its moisture content may change greatly, if the tunnel needs to pass through a fault fracture zone, in order to deal with the risk of large deformation that may occur, risk response measures usually need to be formulated in advance, which requires prior Conduct construction safety analysis. With the development of computer technology, numerical simulation has gradually become one of the important means to analyze the safety of tunnel construction. No matter which of the many methods such as finite element method, finite difference, discrete element method, and block discrete element method is used, the accuracy of the analysis results of the established numerical simulation model is consistent with the input rock mass mechanical parameters and joint planes. parameters are closely related. Among these parameters, the accuracy of rock mass mechanical parameters is particularly important, mainly elastic modulus, cohesion, and internal friction angle.

室内实验是确定岩石力学特征的重要手段,通过其可以得到岩石的弹性模量、粘聚力和内摩擦角等基本力学参数。岩体是由岩石和诸多结构面组成的复合体。结构面是岩体的软弱交接面,其抗剪、抗拉等强度均低于岩石。受结构面的影响,岩体的力学参数会显著低于岩石的力学参数。基于目前的实验条件,确定岩体弹性模量、粘聚力和内摩擦角等基本力学参数的实验依然无法得到有效开展,导致岩体力学参数的确定方法存在较大的主观性,不利于隧道施工安全的仿真分析,更无法有效开展不同含水率情况下的隧道变形分析,给隧道变形预测带来了极大的不便。Indoor experiments are an important means to determine the mechanical characteristics of rocks, through which basic mechanical parameters such as elastic modulus, cohesion and internal friction angle of rocks can be obtained. Rock mass is a complex composed of rocks and many structural surfaces. The structural surface is the weak interface of rock mass, and its shear and tensile strength are lower than that of rock. Affected by structural planes, the mechanical parameters of rock mass will be significantly lower than those of rock. Based on the current experimental conditions, experiments to determine basic mechanical parameters such as rock mass elastic modulus, cohesion and internal friction angle still cannot be effectively carried out, resulting in a large subjectivity in the method of determining rock mass mechanical parameters, which is not conducive to tunnels. Simulation analysis of construction safety cannot effectively carry out tunnel deformation analysis under different water contents, which brings great inconvenience to tunnel deformation prediction.

发明内容Contents of the invention

本发明提供一种基于含水率的岩体的数值仿真模型参数确定方法,该方法在结合室内岩石力学实验确定岩石力学特征随含水率的变化规律的基础上,采用参数标定方法得到特定含水率情况下的岩体力学参数,进一步基于岩石力学参数和岩体力学参数的映射关系确定岩体力学参数的变化关系式,从而得到不同含水率情况下的岩体数值仿真模型实现参数的计算,能够高效且高精度获得隧道的变形数据,为隧道施工安全的数值仿真分析提供指导。该方法的具体技术方案如下:The present invention provides a method for determining parameters of a numerical simulation model of rock mass based on moisture content. This method uses a parameter calibration method to obtain specific moisture content conditions based on combining indoor rock mechanics experiments to determine the changing rules of rock mechanical characteristics with moisture content. The rock mass mechanical parameters under the conditions are further determined based on the mapping relationship between the rock mechanical parameters and the rock mass mechanical parameters, so as to obtain the calculation of parameters of the rock mass numerical simulation model under different water contents, which can efficiently And the deformation data of the tunnel can be obtained with high precision, providing guidance for numerical simulation analysis of tunnel construction safety. The specific technical solution of this method is as follows:

一种基于含水率的岩体的数值仿真模型参数确定方法,包括以下步骤:A method for determining parameters of a numerical simulation model of rock mass based on water content, including the following steps:

节理裂隙仿真模型的生成,具体包括:对隧道掌子面进行拍照,采用DeepLabv3+算法对照片进行分析,提取出节理裂隙的特征,该特征包含长度、数量和间距;采用Monte-Carlo方法重新生成与节理裂隙的特征相吻合的节理裂隙仿真模型;The generation of the joint crack simulation model specifically includes: taking photos of the tunnel face, using the DeepLabv3+ algorithm to analyze the photos, and extracting the characteristics of the joint cracks, which include length, number, and spacing; using the Monte-Carlo method to regenerate and A joint crack simulation model consistent with the characteristics of joint cracks;

参数随含水率的变化关系式的获取,具体包括:采用室内实验方式确定岩石在不同饱和状态下的参数,并通过拟合处理得到各参数随含水率的变化关系式;参数包括弹性模量、粘聚力和内摩擦角;Obtaining the relationship expression of parameters changing with water content specifically includes: using indoor experiments to determine the parameters of rocks under different saturation states, and obtaining the relationship expression of each parameter changing with water content through fitting processing; parameters include elastic modulus, Cohesion and internal friction angle;

对岩体的参数进行标定,具体是:结合现场所监测的变形数据,采用参数标定方法确定某一含水率状态下岩体力学参数;Calibrate the parameters of the rock mass, specifically: combined with the deformation data monitored on site, use the parameter calibration method to determine the mechanical parameters of the rock mass under a certain moisture content state;

获取不同含水率下的岩体力学参数,具体是:将所得岩体力学参数代入参数随含水率的变化关系式中得到不同含水率下的岩体力学参数。Obtain the rock mass mechanical parameters under different water contents, specifically: substitute the obtained rock mass mechanical parameters into the relationship between parameters changing with water content to obtain the rock mass mechanical parameters under different water contents.

优选的,节理裂隙仿真模型的生成中:Preferably, the joint and crack simulation model is being generated:

对隧道掌子面进行拍照,具体拍摄5-10张;对同一地层状况下的5-10个掌子面进行拍照,取隧道掌子面的节理裂隙分布特征的平均值为节理裂隙仿真模型的建模依据。Take photos of the tunnel face, specifically 5-10 photos; take photos of 5-10 tunnel faces under the same stratigraphic conditions, and take the average value of the joint and crack distribution characteristics of the tunnel face as the joint and crack simulation model Modeling basis.

优选的,参数随含水率的变化关系式的获取中:Preferably, the relationship between parameters changing with moisture content is obtained:

岩石的含水率状态包括干燥、20%、40%、60%、80%和100%;Moisture content states of rock include dry, 20%, 40%, 60%, 80% and 100%;

岩石中弹性模量、粘聚力和内摩擦角分别随含水率的变化如下:The elastic modulus, cohesion and internal friction angle in rocks change with water content as follows:

弹性模量随含水率变化如下式:The elastic modulus changes with moisture content as follows:

E=E0e-AwE=E 0 e -Aw ;

其中:E为某一含水率情况下的岩石弹性模量,E0为岩石干燥状态下的弹性模量,w为含水率,A为弹性模量折减系数;Among them: E is the elastic modulus of rock under a certain moisture content, E 0 is the elastic modulus of rock in a dry state, w is the moisture content, and A is the elastic modulus reduction coefficient;

粘聚力随含水率的变化成线性关系变化如下:The cohesion changes linearly with changes in moisture content as follows:

c=k1w+c0c=k 1 w+c 0 ;

其中:c是岩石在某一含水率状态下的粘聚力,c0是岩石在干燥状态下的粘聚力,k1是对应的岩石的粘聚力随含水率变化的系数;Among them: c is the cohesion of rock in a certain moisture content state, c 0 is the cohesion of rock in dry state, k 1 is the corresponding coefficient of rock cohesion changing with moisture content;

内摩擦角随含水率的变化成线性关系变化如下:The internal friction angle changes linearly with the change of moisture content as follows:

其中:是岩石在某一含水率状态下的内摩擦角,/>是岩石在干燥状态下的内摩擦角,k2是对应的岩石的内摩擦角随含水率变化的系数。in: is the internal friction angle of rock under a certain moisture content,/> is the internal friction angle of the rock in the dry state, and k 2 is the corresponding coefficient of the internal friction angle of the rock that changes with the moisture content.

优选的,对岩体的参数进行标定中:Preferably, the parameters of the rock mass are being calibrated:

采用全站仪对隧道的变形数据进行跟踪量测,该变形数据包括拱顶沉降和隧道的内轮廓宽度;A total station is used to track and measure the deformation data of the tunnel, which includes the vault settlement and the inner contour width of the tunnel;

参数标定成功的判别标准为:基于输入的岩体力学参数,通过参数标定方法中数值仿真模型计算得到的隧道的变形数据与现场所监测的变形数据相吻合。The criterion for successful parameter calibration is: based on the input rock mass mechanical parameters, the deformation data of the tunnel calculated through the numerical simulation model in the parameter calibration method is consistent with the deformation data monitored on site.

优选的,参数标定过程中:若计算得到的隧道的变形数据大于现场所监测的变形数据,则增大岩体的力学参数进行重新标定;若计算得到的隧道的变形数据小于现场所监测的变形数据,则减小岩体的力学参数进行重新标定。Preferably, during the parameter calibration process: if the calculated deformation data of the tunnel is greater than the deformation data monitored on site, increase the mechanical parameters of the rock mass and recalibrate; if the calculated deformation data of the tunnel is less than the deformation monitored on site, If the data is obtained, the mechanical parameters of the rock mass will be reduced and recalibrated.

优选的,隧道的变形随内摩擦角和粘聚力的减小呈现线性增加,如下式:Preferably, the deformation of the tunnel increases linearly as the internal friction angle and cohesion decrease, as shown in the following formula:

D=B1c+d0 D=B 1 c+d 0 ,

其中:D为隧道变形,B1、B2为常数,c和分别代表粘聚力和内摩擦角,d0为粘聚力或内摩擦角为0时的隧道变形;Among them: D is the tunnel deformation, B 1 and B 2 are constants, c and represent the cohesion force and internal friction angle respectively, and d 0 is the tunnel deformation when the cohesion force or internal friction angle is 0;

隧道的变形随弹性模量的降低成反比例函数形式增加如下式:The deformation of the tunnel increases as an inversely proportional function as the elastic modulus decreases, as follows:

其中:D为隧道变形,C1、C2为常数,x为弹性模量。Among them: D is the tunnel deformation, C 1 and C 2 are constants, and x is the elastic modulus.

优选的,获取不同含水率下的岩体力学参数中岩体中弹性模量、粘聚力和内摩擦角分别随含水率的变化如下:Preferably, the elastic modulus, cohesion and internal friction angle of the rock mass in the mechanical parameters of the rock mass under different water contents are obtained as follows:

弹性模量随含水率变化如下式:The elastic modulus changes with moisture content as follows:

Erm=Erm0e-AwE rm =E rm0 e -Aw ;

其中:Erm为某一含水率情况下的岩体弹性模量,Erm0为岩体干燥状态下的弹性模量。Among them: E rm is the elastic modulus of rock mass under a certain moisture content, and E rm0 is the elastic modulus of rock mass in dry state.

粘聚力随含水率的变化成线性关系变化如下:The cohesion changes linearly with changes in moisture content as follows:

crm=k1w+crm0c rm = k 1 w + c rm0 ;

其中:crm是岩体在某一含水率状态下的粘聚力,crm0是岩体在干燥状态下的粘聚力。Among them: c rm is the cohesion of rock mass in a certain moisture content state, and cr rm0 is the cohesion of rock mass in dry state.

内摩擦角随含水率的变化成线性关系变化如下:The internal friction angle changes linearly with the change of moisture content as follows:

其中:是岩体在某一含水率状态下的内摩擦角,/>是岩体在干燥状态下的内摩擦角。in: is the internal friction angle of the rock mass under a certain moisture content,/> is the internal friction angle of the rock mass in the dry state.

优选的,参数标定中允许计算得到的隧道的变形数据与现场所监测的变形数据误差范围不超过5%。Preferably, the parameter calibration allows the error range between the calculated tunnel deformation data and the field-monitored deformation data to be no more than 5%.

附图说明Description of drawings

图1为本发明实施例1中的数值仿真模型参数确定方法的流程示意图;Figure 1 is a schematic flow chart of a method for determining parameters of a numerical simulation model in Embodiment 1 of the present invention;

图2为本发明实施例1中不同工况下的莫尔圆示意图;Figure 2 is a schematic diagram of Mohr's circle under different working conditions in Embodiment 1 of the present invention;

图3是本发明实施例1中初期支护的单元体的示意图;Figure 3 is a schematic diagram of the initial support unit in Embodiment 1 of the present invention;

图4是本发明实施例1中计算得到的隧道变形示意图。Figure 4 is a schematic diagram of tunnel deformation calculated in Embodiment 1 of the present invention.

具体实施方式Detailed ways

下面结合附图对本发明的实施例进行详细阐述,以使本发明的优点和特征能更易于被本领域技术人员理解,从而对本发明的保护范围做出更为清楚明确的界定。The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the protection scope of the present invention can be more clearly defined.

实施例:Example:

一种基于含水率的岩体的数值仿真模型参数确定方法,其具体过程如图1所示,具体包括如下步骤:A method for determining the parameters of a numerical simulation model of rock mass based on moisture content. The specific process is shown in Figure 1, which specifically includes the following steps:

步骤一、参数随含水率的变化关系式的获取(即基于室内试验得到岩石力学参数随含水率变化),具体包括:采用室内实验方式确定岩石在不同饱和状态下的参数,并通过拟合处理得到各参数随含水率的变化关系式;参数包括弹性模量、粘聚力和内摩擦角。详情如下:Step 1. Obtain the relationship between parameters and water content (that is, obtain rock mechanical parameters as water content changes based on indoor experiments). Specifically, it includes: using indoor experiments to determine the parameters of rocks in different saturated states, and processing them through fitting. The relationship between each parameter changing with moisture content is obtained; the parameters include elastic modulus, cohesion and internal friction angle. Details are as follows:

通过开展岩石的应力-应变测试,确定其在不同含水率状态下的弹性模量,测试方法如下:首先通过单轴加载得到岩石的强度,再取另一个同样的岩样开展加卸载试验,加载至岩石强度的70%后卸载,如此循环3-5次,得到加卸载期间岩石的应力-应变曲线,然后取最后一次卸载时的弹性模量作为岩石的弹性模量,计算公式如下式:By carrying out stress-strain testing of rock, its elastic modulus under different moisture content conditions is determined. The testing method is as follows: first, the strength of the rock is obtained through uniaxial loading, and then another identical rock sample is taken to carry out a loading and unloading test. After reaching 70% of the rock strength, unload, repeat this cycle 3-5 times, and obtain the stress-strain curve of the rock during loading and unloading. Then take the elastic modulus of the last unloading as the elastic modulus of the rock. The calculation formula is as follows:

其中:Δσ和Δε分别为最后一次卸载期间的应力和应变改变量。Among them: Δσ and Δε are the stress and strain changes during the last unloading period respectively.

假设岩石在某含水率情况下的强度为30MPa,逐次加载得到岩石应力-应变参数如表1所示:Assuming that the strength of rock at a certain moisture content is 30MPa, the rock stress-strain parameters obtained by successive loading are shown in Table 1:

表1岩石应力-应变参数统计表Table 1 Statistical table of rock stress-strain parameters

另取一批岩石开展特定含水率情况下的三轴试验,分别测得围压为2、4、6、8(MPa)时的岩石强度,并结合单轴压缩实验强度,在剪应力-正应力坐标系中绘制莫尔圆,通过拟合得到岩石在该含水率状态下的剪切强度变化曲线,从而得到岩石的粘聚力和内摩擦角。Another batch of rocks were selected to conduct triaxial tests under specific water content conditions. The rock strengths were measured when the confining pressure was 2, 4, 6, and 8 (MPa). Combined with the uniaxial compression experimental strength, the shear stress-normal Mohr's circle is drawn in the stress coordinate system, and the shear strength change curve of the rock under this moisture content state is obtained through fitting, thereby obtaining the cohesion force and internal friction angle of the rock.

假设得到某含水率情况下岩石的三轴强度如下表2:Assume that the triaxial strength of rock under a certain moisture content is obtained as shown in Table 2:

表2某含水率情况下岩石的三轴强度统计表Table 2 Statistical table of triaxial strength of rocks under a certain moisture content

工况Working conditions 11 22 33 44 55 围压/MPaConfining pressure/MPa 00 22 44 66 88 强度/MPaStrength/MPa 3030 33.333.3 36.936.9 40.640.6 43.943.9

可进一步绘制不同工况下的莫尔圆如图2所示。图2中:半圆的最左边横坐标为围压,最右边点的横坐标为强度。可近似绘制一条直线,使得该直线与这些半圆相切。则该直线的斜率即为内摩擦角与竖坐标轴的交点即为粘聚力c,由此可得该含水率情况下的粘聚力和内摩擦角。Mohr's circles under different working conditions can be further drawn as shown in Figure 2. In Figure 2: the leftmost abscissa of the semicircle is the confining pressure, and the abscissa of the rightmost point is the intensity. A straight line can be drawn approximately such that it is tangent to these semicircles. Then the slope of the straight line is the internal friction angle The intersection point with the vertical axis is the cohesion c, from which the cohesion and internal friction angle at this moisture content can be obtained.

最后采用origin或Excel等软件,采用回归分析方法拟合得到岩石的这些力学参数随含水率的变化关系式如下:Finally, using software such as origin or Excel, the regression analysis method is used to fit the relationship between the changes in these mechanical parameters of the rock with the water content as follows:

弹性模量随含水率变化如下式:The elastic modulus changes with moisture content as follows:

E=E0e-AwE=E 0 e -Aw ;

其中:E为某一含水率情况下的岩石弹性模量,E0为岩石干燥状态下的弹性模量,w为含水率,A为弹性模量折减系数;Among them: E is the elastic modulus of rock under a certain moisture content, E 0 is the elastic modulus of rock in a dry state, w is the moisture content, and A is the elastic modulus reduction coefficient;

粘聚力随含水率的变化成线性关系变化如下:The cohesion changes linearly with changes in moisture content as follows:

c=k1w+c0c=k 1 w+c 0 ;

其中:c是岩石在某一含水率状态下的粘聚力,c0是岩石在干燥状态下的粘聚力,k1是对应的岩石的粘聚力随含水率变化的系数;Among them: c is the cohesion of rock in a certain moisture content state, c 0 is the cohesion of rock in dry state, k 1 is the corresponding coefficient of rock cohesion changing with moisture content;

内摩擦角随含水率的变化成线性关系变化如下:The internal friction angle changes linearly with the change of moisture content as follows:

其中:是岩石在某一含水率状态下的内摩擦角,/>是岩石在干燥状态下的内摩擦角,k2是对应的岩石的内摩擦角随含水率变化的系数。in: is the internal friction angle of rock under a certain moisture content,/> is the internal friction angle of the rock in the dry state, and k 2 is the corresponding coefficient of the internal friction angle of the rock that changes with the moisture content.

步骤二、节理裂隙仿真模型的生成,具体包括:Step 2: Generation of joint crack simulation model, including:

步骤2.1、基于DeepLabv3+对掌子面节理裂隙特征进行统计,具体是:对隧道掌子面进行拍照,采用DeepLabv3+算法对照片进行分析,提取出节理裂隙的特征,该特征包含长度、数量和间距;此处优选:对隧道掌子面进行拍照应拍摄5-10张,以使得图像分析结果能够更加真实地反映当前隧道掌子面的节理裂隙分布特征,此外,应对同一地层状况下的5-10个隧道掌子面进行拍照,取隧道掌子面节理裂隙分布特征的平均值为数值仿真模型的节理裂隙特征建模依据。Step 2.1. Based on DeepLabv3+, make statistics on the joint crack characteristics of the tunnel face. Specifically, take photos of the tunnel tunnel face, use the DeepLabv3+ algorithm to analyze the photos, and extract the characteristics of the joint cracks, which include length, number, and spacing; Preferred here: 5-10 photos should be taken of the tunnel face, so that the image analysis results can more truly reflect the joint and crack distribution characteristics of the current tunnel face. In addition, 5-10 photos should be taken under the same stratigraphic conditions. Take pictures of each tunnel face, and take the average value of the joint and crack distribution characteristics of the tunnel face as the basis for modeling the joint and crack characteristics of the numerical simulation model.

步骤2.2、基于Monte-Carlo方法生成节理裂隙仿真模型,具体是:采用Monte-Carlo方法生成与掌子面节理裂隙特征相吻合的节理裂隙仿真模型,并导入到3DEC块体离散元软件中,进一步采用剖分等方法对导入的模型进行分区,从而预先确定隧道开挖范围以方便隧道开挖的仿真分析,然后将建立的模型划分为若干个网格,通过赋予网格以岩体的力学参数经验值来模拟实际岩体,进一步对模型的底面和侧面进行约束,并施加重力场模拟隧道开挖前的地层应力状态,之后进行隧道开挖的仿真计算,从而得到隧道变形的仿真结果。Step 2.2. Generate a joint crack simulation model based on the Monte-Carlo method. Specifically, use the Monte-Carlo method to generate a joint crack simulation model consistent with the joint crack characteristics of the tunnel face, and import it into the 3DEC block discrete element software. Use methods such as segmentation to partition the imported model to predetermine the tunnel excavation range to facilitate the simulation analysis of tunnel excavation. Then divide the established model into several grids, and assign the mechanical parameters of the rock mass to the grids. Empirical values are used to simulate the actual rock mass, and the bottom and sides of the model are further constrained, and a gravity field is applied to simulate the stratigraphic stress state before tunnel excavation, and then the simulation calculation of tunnel excavation is performed to obtain the simulation results of tunnel deformation.

数值仿真模型的创建思路如下:首先生成一个长方体,采用剖分方式对该长方体进行分区,剖分出的一部分区域用于模拟隧道开挖,其余区域用于模拟隧道周围岩体。剖分之后,再次采用对该长方体进行剖分,得到剖分后的长方体。The idea of creating a numerical simulation model is as follows: first generate a cuboid, use a subdivision method to partition the cuboid, part of the subdivided area is used to simulate tunnel excavation, and the remaining area is used to simulate the rock mass around the tunnel. After segmentation, the cuboid is segmented again to obtain the segmented cuboid.

此时,该长方体包括剖分面和剖分后的块体两部分。对剖分后的长方体进行网格划分,达到将剖分后的块体划分为若干个更小的单元体。此时,起初创建的长方体由两部分组成,即剖分面和单元体。赋予剖分面以节理裂隙的力学参数,赋予单元体以岩体的力学参数,从而达到模拟实际岩体的目的。进一步约束该长方体的底面和侧面,并对全部单元体施加一个重力加速度,模拟实际环境下的重力影响。此时,岩体创建工作完成,生成的模型即可认为是数值仿真模型。进一步展开计算,每计算一次3DEC会就算一次所有单元体的不平衡力,当不平衡力小到一定程度时,如1e-5,即可认为已经达到平衡,此时,即可认为地应力已经平衡,即当前该长方体的应力状态和实际环境下的地层应力状态相同。At this time, the cuboid consists of two parts: the split surface and the split block. The divided cuboid is meshed to divide the divided block into several smaller units. At this point, the initially created cuboid consists of two parts, namely the splitting surface and the unit body. The split plane is given the mechanical parameters of joints and fissures, and the unit body is given the mechanical parameters of the rock mass, thereby achieving the purpose of simulating the actual rock mass. The bottom and sides of the cuboid are further constrained, and a gravity acceleration is applied to all unit bodies to simulate the influence of gravity in the actual environment. At this point, the rock mass creation work is completed, and the generated model can be considered a numerical simulation model. To further expand the calculation, each calculation of 3DEC will calculate the unbalanced force of all units. When the unbalanced force is small to a certain extent, such as 1e-5, it can be considered that equilibrium has been reached. At this time, the ground stress can be considered to have been reached. Equilibrium means that the current stress state of the cuboid is the same as the formation stress state in the actual environment.

需要注意的是,此时,该长方体的单元体已经产生变形。在进行隧道开挖分析时,需要对变形等内容进行归零操作,表示隧道开挖前地层无位移且存在一定的应力状态。隧道开挖模拟时,通过删除隧道范围内的单元体,达到模拟隧道开挖的目的。此外,采用类似的方法,在隧道轮廓处施加另一部分模拟初期支护的单元体,并赋予其初期支护的力学参数,模拟实际施工期间的初期支护。继续进行计算,当不平衡力足够小时,即可认为隧道处于稳定状况。此时,模拟初期支护的单元体会产生变形,该变形即为隧道变形的模拟值。如图3即为建立的长方体,其中:马蹄形黑色的区域即为剖分出的隧道区域,看似杂乱的黑色线条即为生成的节理裂隙。图4所示为计算后的隧道变形,如图4所示(右下角区域黑色箭头所指的即为剖分该立方体所形成的剖分面,黑色椭圆框即为剖分形成的块体),可以看出,其有诸多小三角形,此小三角形即为形成的单元体;其在三维空间是四面体;在黑色的通过赋予黑色线条以节理裂隙的力学参数,并赋予这些单元体以岩体的力学参数,达到模拟实际岩体的目的。It should be noted that at this time, the unit body of the cuboid has been deformed. When performing tunnel excavation analysis, it is necessary to reset the deformation and other contents to zero, which means that the ground layer has no displacement and a certain stress state before tunnel excavation. When simulating tunnel excavation, the purpose of simulating tunnel excavation is achieved by deleting the units within the tunnel range. In addition, a similar method is used to apply another part of the unit body to simulate the initial support at the tunnel contour, and give it the mechanical parameters of the initial support to simulate the initial support during the actual construction. Continuing with the calculation, when the unbalanced force is small enough, the tunnel can be considered to be in a stable condition. At this time, the unit body simulating the initial support will deform, and this deformation is the simulated value of the tunnel deformation. Figure 3 shows the established cuboid, in which the horseshoe-shaped black area is the divided tunnel area, and the seemingly messy black lines are the generated joint cracks. Figure 4 shows the calculated tunnel deformation, as shown in Figure 4 (the black arrow in the lower right corner points to the splitting surface formed by splitting the cube, and the black oval frame is the block formed by splitting) , it can be seen that it has many small triangles, which are the formed unit bodies; it is a tetrahedron in the three-dimensional space; the black lines in the black pass are given the mechanical parameters of joints and cracks, and these unit bodies are given the rock Mechanical parameters of the body to achieve the purpose of simulating the actual rock mass.

步骤三、对岩体的参数进行标定(即基于考虑节理裂隙的数值仿真模型和现场监测的变形数据对岩体参数进行标定),具体是:结合现场所监测的变形数据,采用参数标定方法确定某一含水率状态下岩体力学参数,如下:Step 3: Calibrate the parameters of the rock mass (that is, calibrate the parameters of the rock mass based on a numerical simulation model that considers joints and cracks and the deformation data monitored on site). Specifically, it is determined by using the parameter calibration method based on the deformation data monitored on site. The mechanical parameters of rock mass under a certain moisture content state are as follows:

采用全站仪对包含拱顶沉降和水平收敛(隧道内轮廓宽度)的隧道的变形数据进行跟踪量测,具体是:先基于经验确定岩体力学参数的值,然后将该力学参数输入步骤二所建立的模型中进行计算,得到隧道变形的仿真结果,然后进行判断,具体是:若该仿真结果大于基于全站仪量测的结果,则增大岩体力学参数,再次进行计算,会使得计算得到的隧道变形值减小;若仿真结果小于全站仪量测的结果,则减小岩体的力学参数,再次进行计算,会使得计算得到的隧道变形增加。通过调整三维仿真模型中输入的岩体力学参数,使得计算得到的隧道变形数据不断趋近于量测值,如输入岩体某一参数得到的变形明显大于量测结果,则调大岩体输入参数,重新计算。参数标定成功的判别标准为:基于输入的岩体力学参数,通过参数标定方法中数值仿真模型计算得到的隧道的变形数据与现场所监测的变形数据相吻合。Use a total station to track and measure the deformation data of the tunnel including vault settlement and horizontal convergence (tunnel inner contour width). Specifically: first determine the values of the rock mass mechanical parameters based on experience, and then input the mechanical parameters into step 2. Calculate in the established model to obtain the simulation results of tunnel deformation, and then make a judgment. Specifically: if the simulation results are greater than the results based on total station measurement, increase the rock mass mechanical parameters and perform calculations again, which will make The calculated tunnel deformation value decreases; if the simulation result is smaller than the total station measurement result, then reduce the mechanical parameters of the rock mass and perform the calculation again, which will increase the calculated tunnel deformation. By adjusting the rock mass mechanical parameters input in the three-dimensional simulation model, the calculated tunnel deformation data will continue to approach the measured value. If the deformation obtained by inputting a certain parameter of the rock mass is significantly greater than the measured result, increase the rock mass input. Parameters, recalculate. The criterion for successful parameter calibration is: based on the input rock mass mechanical parameters, the deformation data of the tunnel calculated through the numerical simulation model in the parameter calibration method is consistent with the deformation data monitored on site.

本实施例优选的:Preferred in this embodiment:

岩石的含水率状态包括干燥(即0%)、20%、40%、60%、80%和100%,百分数为岩石中的含水率。The moisture content status of the rock includes dry (i.e. 0%), 20%, 40%, 60%, 80% and 100%, and the percentage is the moisture content in the rock.

隧道的变形随内摩擦角和粘聚力的减小呈现线性增加,如下式:The deformation of the tunnel increases linearly with the decrease of the internal friction angle and cohesion, as shown in the following formula:

D=B1c+d0 D=B 1 c+d 0 ,

其中:D为隧道变形,B1、B2为常数,c和分别代表粘聚力和内摩擦角,d0为粘聚力或内摩擦角为0时的隧道变形;Among them: D is the tunnel deformation, B 1 and B 2 are constants, c and represent the cohesion force and internal friction angle respectively, and d 0 is the tunnel deformation when the cohesion force or internal friction angle is 0;

隧道的变形随弹性模量的降低成反比例函数形式增加如下式:The deformation of the tunnel increases as an inversely proportional function as the elastic modulus decreases, as follows:

其中:D为隧道变形,C1、C2为常数,x为弹性模量。Among them: D is the tunnel deformation, C 1 and C 2 are constants, and x is the elastic modulus.

本实施例中优选的,B1、B2的取值范围在1e-4~1e-3范围内,C1的取值范围在-10~-100范围内,C2的取值范围在-0.1~-2范围内。Preferably in this embodiment, the value range of B 1 and B 2 is in the range of 1e-4 to 1e-3, the value range of C 1 is in the range of -10 to -100, and the value range of C 2 is in the range of - Within the range of 0.1~-2.

当偏差在可接受范围内时,如5%,即可认为输入的模型参数是可靠的,此时输入的岩体力学参数即可认为是隧道变形监测位置附近岩体的力学参数,此时岩体力学参数对应的含水率可通过在隧道监测点附近取样进行室内含水率测试得到,如表3:When the deviation is within the acceptable range, such as 5%, the input model parameters can be considered reliable. At this time, the input rock mass mechanical parameters can be considered as the mechanical parameters of the rock mass near the tunnel deformation monitoring position. At this time, the rock mass mechanical parameters are The moisture content corresponding to the body mechanics parameters can be obtained by sampling indoor moisture content near the tunnel monitoring point, as shown in Table 3:

表3变形监测数据统计表Table 3 Deformation monitoring data statistics table

步骤四、获取不同含水率下的岩体力学参数(基于岩石力学参数和岩体力学参数的映射关系,得到不同含水率情况下的岩体力学参数),具有是:将所得岩体力学参数代入参数随含水率的变化关系式中得到不同含水率下的岩体力学参数。本实施例优选的:Step 4: Obtain the rock mass mechanical parameters under different water contents (based on the mapping relationship between the rock mechanical parameters and the rock mass mechanical parameters, obtain the rock mass mechanical parameters under different water contents). The following is: Substitute the obtained rock mass mechanical parameters into The rock mass mechanical parameters under different water contents are obtained from the relationship between parameters changing with water content. Preferred in this embodiment:

岩体力学参数中弹性模量、粘聚力和内摩擦角分别随含水率的变化如下:The elastic modulus, cohesion and internal friction angle among the rock mass mechanical parameters change with the water content as follows:

弹性模量随含水率变化如下式:The elastic modulus changes with moisture content as follows:

Erm=Erm0e-AwE rm =E rm0 e -Aw ;

其中:Erm为某一含水率情况下的岩体弹性模量,Erm0为岩体干燥状态下的弹性模量。Among them: E rm is the elastic modulus of rock mass under a certain moisture content, and E rm0 is the elastic modulus of rock mass in dry state.

粘聚力随含水率的变化成线性关系变化如下:The cohesion changes linearly with changes in moisture content as follows:

crm=k1w+crm0c rm = k 1 w + c rm0 ;

其中:crm是岩体在某一含水率状态下的粘聚力,crm0是岩体在干燥状态下的粘聚力。Among them: c rm is the cohesion of rock mass in a certain moisture content state, and cr rm0 is the cohesion of rock mass in dry state.

内摩擦角随含水率的变化成线性关系变化如下:The internal friction angle changes linearly with the change of moisture content as follows:

其中:是岩体在某一含水率状态下的内摩擦角,/>是岩体在干燥状态下的内摩擦角。in: is the internal friction angle of the rock mass under a certain moisture content,/> is the internal friction angle of the rock mass in the dry state.

本发明方案的具体应用案例:Specific application cases of the solution of the present invention:

案例1:张吉怀铁路新华山隧道需穿越一条断层破碎带,破碎带内岩体裂隙发育,能够为地下水渗流提供良好的渗流通道。在无降雨情况下,隧道周边岩体含水率较低。降雨情况下,地表水会在沿该破碎带进行流动,从而逐步渗流至隧道附近,导致隧道周围岩体的含水率增加。自然状况下,水在岩体中的渗流是缓慢的,使得在隧道靠近破碎带区域不同位置处岩体的含水率存在较大差异。如,在破碎带位置处的含水率为100%,在距破碎带10m处的含水率为80%,在距50m位置处的含水率为50%。在远离断层破碎带的区域(如距破碎带100m)进行开挖时,隧道变形在容许范围以内,此时岩体的含水率约10%。但在穿越断层破碎带期间,若不采取额外加固措施,则隧道的变形可能超出容许值,甚至引起支护体系开裂、破坏,造成工期延误、造价增加等问题。若盲目采取大量的加固措施,则会导致材料浪费,工程造价增加等问题。为此,需要分析岩体不同含水率情况下的施工安全性,进而为加固措施的提出提供一定的理论依据。Case 1: The Xinhuashan Tunnel of the Zhangjihuai Railway needs to pass through a fault fracture zone. The rock mass cracks in the fracture zone are developed, which can provide a good seepage channel for groundwater seepage. In the absence of rainfall, the moisture content of the rock mass around the tunnel is low. During rainfall, surface water will flow along the fracture zone and gradually seep to the vicinity of the tunnel, causing the moisture content of the rock mass around the tunnel to increase. Under natural conditions, the seepage of water in the rock mass is slow, resulting in large differences in the moisture content of the rock mass at different locations near the fracture zone of the tunnel. For example, the moisture content at the location of the crushing zone is 100%, the moisture content at a location 10m away from the crushing zone is 80%, and the moisture content at a location 50m away from the crushing zone is 50%. When excavating in an area far away from the fault fracture zone (such as 100m away from the fracture zone), the tunnel deformation is within the allowable range, and the moisture content of the rock mass at this time is about 10%. However, if additional reinforcement measures are not taken during the process of crossing the fault fracture zone, the deformation of the tunnel may exceed the allowable value, and even cause cracks and damage to the support system, resulting in delays in the construction period, increased costs, and other problems. If a large number of reinforcement measures are taken blindly, it will lead to problems such as material waste and increased project costs. To this end, it is necessary to analyze the construction safety under different moisture contents of the rock mass, thereby providing a certain theoretical basis for proposing reinforcement measures.

然而,不同含水率情况下,岩体的力学参数如何确定无法知晓,室内岩石力学实验只能得到岩石在不同含水率情况下的力学参数。基于本发明,可以先开展室内岩石力学实验可以得到岩石弹性模量在干燥状态和100%含水率下分别为36.30GPa和8.50GPa,从而得到弹性模量折减系数A=1.45,即岩石弹性模量随含水率的变化关系如下:However, it is unknown how to determine the mechanical parameters of rock mass under different water contents. Indoor rock mechanics experiments can only obtain the mechanical parameters of rocks under different water contents. Based on the present invention, indoor rock mechanics experiments can be carried out first to obtain that the rock elastic modulus in the dry state and 100% moisture content are 36.30GPa and 8.50GPa respectively, thereby obtaining the elastic modulus reduction coefficient A = 1.45, that is, the rock elastic modulus The relationship between the amount and moisture content is as follows:

E=36.3e-1.45wE=36.3e -1.45w .

基于本发明可知,岩体弹性模量随含水率的变化关系如下:Based on the present invention, it can be seen that the relationship between the elastic modulus of rock mass and the change of water content is as follows:

Erm=Erm0e-1.45wE rm =E rm0 e -1.45w .

上式中,Erm0是未知的,但可通过参数标定加以确定。In the above formula, E rm0 is unknown, but it can be determined through parameter calibration.

进一步基于现场实测数据对岩体力学参数进行标定,得到10%含水率情况下岩体的弹性模量约为1.04GPa,即1.04=Erm0e-1.45×0.1,可得Erm0=1.2GPa,从而得到岩体的弹性模量随含水率的变化率,如下式所示:The mechanical parameters of the rock mass were further calibrated based on the field measured data, and the elastic modulus of the rock mass at 10% moisture content was obtained to be approximately 1.04GPa, that is, 1.04=E rm0 e -1.45×0.1 , and it can be obtained that E rm0 =1.2GPa, Thus, the rate of change of the elastic modulus of the rock mass with the water content is obtained, as shown in the following formula:

Erm=1.2e-1.45wE rm =1.2e -1.45w .

从而可以得到岩体弹性模量随含水率的变化。岩体粘聚力和内摩擦角随含水率的变化关系可采用类似方法得到,最终可确定不同含水率情况下岩体的力学参数。将这些参数代入所建立的三维仿真模型中,可计算得到不同含水率情况下隧道变形。汇总如表4所示:Thus, the change of rock mass elastic modulus with water content can be obtained. The relationship between rock mass cohesion and internal friction angle with water content can be obtained using a similar method, and finally the mechanical parameters of the rock mass under different water contents can be determined. By substituting these parameters into the established three-dimensional simulation model, the tunnel deformation under different moisture contents can be calculated. The summary is shown in Table 4:

表4采用本发明方法不同含水率情况下岩体力学参数及计算隧道变形Table 4: Rock mass mechanical parameters and calculated tunnel deformation under different water contents using the method of the present invention

根据计算得到的拱顶沉降和水平收敛值,可进一步确定岩体不同含水率情况下应采取的额外加固措施。Based on the calculated vault settlement and horizontal convergence values, additional reinforcement measures that should be taken under different water contents of the rock mass can be further determined.

如果不采用该发明所提出的岩体参数确定方法,可能取不同含水率情况下岩体的力学参数以及计算得到岩体变形如表5所示:If the rock mass parameter determination method proposed by this invention is not used, the mechanical parameters of the rock mass under different water contents may be taken and the calculated rock mass deformation is shown in Table 5:

表5不同含水率情况下岩体力学参数及计算隧道变形Table 5 Rock mass mechanical parameters and calculated tunnel deformation under different water contents

可以看出,采用其他方法评估会导致计算得到的岩体变形较小。若基于此方法不采取一定的加固措施,隧道施工期间可能出现初期支护开裂、破坏等事故。It can be seen that using other methods to evaluate will result in smaller calculated rock mass deformations. If certain reinforcement measures are not taken based on this method, accidents such as initial support cracking and damage may occur during tunnel construction.

案例2:Case 2:

受断层破碎带影响,溧阳焦尾琴隧道周边岩体较破碎。降雨量较大情况下,雨水会渗流至隧道周边。自然状况下,岩体节理裂隙分布不均匀,使得不同区域处岩体的含水率存在一定差异。为保证施工安全,需针对不同含水率情况下隧道变形展开分析。Affected by the fault fracture zone, the rock mass around the Liyang Jiaoweiqin Tunnel is relatively fractured. In the case of heavy rainfall, rainwater will seep to the periphery of the tunnel. Under natural conditions, the joints and fissures of the rock mass are unevenly distributed, resulting in certain differences in the moisture content of the rock mass in different areas. In order to ensure construction safety, it is necessary to analyze the tunnel deformation under different moisture contents.

基于本发明,首先开展岩石力学实验,得到岩石粘聚力随含水率的变化关系如下:Based on the present invention, rock mechanics experiments are first carried out, and the relationship between rock cohesion and moisture content is obtained as follows:

cr=-450w+1750;c r =-450w+1750;

进一步基于现场实测数据对岩体力学参数进行标定,得到30%含水率情况下岩体的粘聚力和内摩擦角分别为395kPa和26°,从而得到岩体的粘聚力和内摩擦角随含水率的变化率,如下式所示:The mechanical parameters of the rock mass were further calibrated based on on-site measured data, and it was found that the cohesion and internal friction angle of the rock mass were 395kPa and 26° respectively under the condition of 30% water content, thus obtaining the cohesion and internal friction angle of the rock mass with varying degrees. The rate of change of moisture content is as shown in the following formula:

crm=-450w+530; crm =-450w+530;

基于上式可得岩体粘聚力和内摩擦角随含水率的变化状况。采用类似的方法可得岩体弹性模量随含水率的变化关系。将这些参数代入所建立的数值模型中,计算可得不同含水率情况下的隧道变形。汇总不同含水率情况下的岩体力学参数及隧道变形如表6所示:Based on the above formula, the changes of rock mass cohesion and internal friction angle with water content can be obtained. Using a similar method, the relationship between the elastic modulus of the rock mass and the water content can be obtained. Substituting these parameters into the established numerical model, the tunnel deformation under different moisture contents can be calculated. A summary of the rock mass mechanical parameters and tunnel deformation under different water contents is shown in Table 6:

表6采用本发明方法不同含水率情况下岩体力学参数及计算隧道变形Table 6: Rock mass mechanical parameters and calculated tunnel deformation under different water contents using the method of the present invention

如果不采用该发明所提出的岩体参数确定方法,可能取不同含水率情况下岩体的力学参数以及计算得到岩体变形如表7:If the rock mass parameter determination method proposed by this invention is not used, the mechanical parameters of the rock mass under different water contents and the calculated rock mass deformation may be obtained as shown in Table 7:

表7不同含水率情况下岩体力学参数及计算隧道变形Table 7 Rock mass mechanical parameters and calculated tunnel deformation under different water contents

可以看出,采用其他方法评估会导致计算得到的岩体变形较大。若基于此方法采取较强的加固措施,可能会使得钢筋、混凝土等用量大幅增加,从而引起工程造价增加。It can be seen that using other evaluation methods will lead to larger calculated rock mass deformations. If strong reinforcement measures are taken based on this method, the amount of steel bars, concrete, etc. may increase significantly, resulting in an increase in project costs.

以上所述仅为本发明的实施例,并非因此限制本发明的专利范围,凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换,或直接或间接运用在其他相关的技术领域,均同理包括在本发明的专利保护范围内。The above are only examples of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description and drawings of the present invention, or directly or indirectly applied to other related technologies fields are equally included in the scope of patent protection of the present invention.

Claims (6)

1. The method for determining the parameters of the numerical simulation model of the rock mass based on the water content is characterized by comprising the following steps of:
the generation of the joint fracture simulation model specifically comprises the following steps: photographing a tunnel face, analyzing the photograph by adopting a deep Labv3+ algorithm, and extracting the characteristics of joint cracks, wherein the characteristics comprise length, quantity and interval; regenerating an joint fracture simulation model which is matched with the characteristics of the joint fracture by adopting a Monte-Carlo method;
the obtaining of the variation relation of the parameters along with the water content specifically comprises the following steps: determining parameters of the rock in different water content states by adopting an indoor experimental mode, and obtaining a change relation of each parameter along with the water content through fitting treatment; parameters include modulus of elasticity, cohesion and internal friction angle;
in the acquisition of the relation of the change of the parameters along with the water content:
the water content state of the rock comprises dry, 20%, 40%, 60%, 80% and 100%;
the change of the elasticity modulus, the cohesion and the internal friction angle in the rock along with the water content is as follows:
the modulus of elasticity varies with the water content as follows:
E=E 0 e -Aw
wherein: e is the elastic modulus of the rock under the condition of a certain water content, E 0 The elastic modulus of the rock in a dry state is represented by w, the water content is represented by w, and the modulus of elasticity is represented by A;
the cohesion changes in a linear relationship with the change in water content as follows:
c=k 1 w+c 0
wherein: c is the cohesive force of the rock under a certain water content state, c 0 Is the cohesion of the rock in the dry state, k 1 Is the coefficient of the corresponding cohesive force of the rock along with the change of the water content;
the internal friction angle varies in a linear relationship with the change in water content as follows:
wherein:is the internal friction angle of rock in a certain water content state,/->Is the internal friction angle, k, of the rock in the dry state 2 Is the coefficient of the change of the internal friction angle of the corresponding rock along with the water content;
the change of the elastic modulus, the cohesion and the internal friction angle in the rock mass along with the water content is as follows:
the modulus of elasticity varies with the water content as follows:
E rm =E rm0 e -Aw
wherein: e (E) rm Modulus of elasticity, E, of rock mass at a certain water content rm0 Is the elastic modulus of the rock mass in a dry state;
the cohesion changes in a linear relationship with the change in water content as follows:
c rm =k 1 w+c rm0
wherein: c rm Is the cohesive force of rock mass under a certain water content state, c rm0 Is the cohesive force of the rock mass in a dry state;
the internal friction angle varies in a linear relationship with the change in water content as follows:
wherein:is the internal friction angle of rock mass under a certain water content state, +.>Is the internal friction angle of the rock mass in a dry state;
calculating the value of the rock elastic modulus under the dry state and the water content of 100% based on the rock elastic modulus obtained by the indoor rock mechanical experiment to obtain an elastic modulus reduction coefficient A;
determination of E by parameter calibration rm0
The change relation of the rock mass cohesive force and the internal friction angle along with the water content is obtained by adopting a similar method;
calibrating parameters of a rock mass, specifically: combining deformation data monitored on site, and determining rock mechanical parameters in a certain water content state by adopting a parameter calibration method;
rock mechanical parameters under different water contents are obtained, and the rock mechanical parameters concretely are: substituting the obtained rock mechanical parameters into a relation equation of the parameters changing with the water content to obtain the rock mechanical parameters under different water contents.
2. The method for determining parameters of a numerical simulation model according to claim 1, wherein in the generation of the joint fracture simulation model:
photographing the tunnel face, and particularly photographing 5-10 sheets; and 5-10 tunnel faces under the same stratum condition are photographed, and an average value of joint fracture distribution characteristics of the tunnel faces is taken as a modeling basis of the joint fracture simulation model.
3. The method for determining parameters of a numerical simulation model according to claim 1, wherein in the calibration of parameters of a rock mass:
tracking and measuring deformation data of the tunnel by adopting a total station, wherein the deformation data comprise vault settlement and inner contour width of the tunnel;
the criterion of successful parameter calibration is as follows: based on the input rock mechanical parameters, the deformation data of the tunnel calculated by the numerical simulation model in the parameter calibration method is identical with the deformation data monitored on site.
4. A method for determining parameters of a numerical simulation model according to claim 3, wherein in the parameter calibration process: if the deformation data of the tunnel obtained through calculation is larger than the deformation data monitored on site, increasing the mechanical parameters of the rock mass for recalibration; and if the calculated deformation data of the tunnel is smaller than the deformation data monitored on site, reducing the mechanical parameters of the rock mass and recalibrating.
5. The method for determining parameters of a numerical simulation model according to claim 4, wherein the deformation of the tunnel exhibits a linear increase with a decrease in internal friction angle and cohesion, as follows:
D=B 1 c+d 0
wherein: d is tunnel deformation, B 1 、B 2 Is constant, c andrespectively represent cohesion and internal friction angle, d 0 Tunnel deformation at 0 for cohesion or internal friction angle;
the deformation of the tunnel increases as an inversely proportional function with the decrease in elastic modulus as follows:
wherein: d is tunnel deformation, C 1 、C 2 Is constant, x is elastic modulus.
6. A method according to claim 3, wherein the error range between the deformation data of the tunnel which is allowed to be calculated in parameter calibration and the deformation data monitored in the field is not more than 5%.
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