严寒地区无砟轨道温度场及轨道板温度梯度预估模型

严寒地区无砟轨道结构的温度荷载取值，是轨道结构设计及服役性能研究急需解决的关键工程问题。基于东北地区大连、沈阳、长春、哈尔滨四个主要城市的历史气象数据及热力学基本原理，建立了CRTS Ⅰ 型板式无砟轨道-路基结构热力学模型，分析在不利气象条件下无砟轨道-路基结构温度场分布特征，拟合计算结果建立了轨道板最大正负温度梯度与气象数据关系预估模型，对东北严寒地区轨道板最不利温度梯度进行讨论。结果表明：CRTS Ⅰ 型板式无砟轨道-路基结构内部温度垂向分布呈非线性，0.2米深度范围内，轨道板及路基的日温度变化幅度较为剧烈，在一日内承受正负温度梯度的交替作用，1.4m深度后路基的温度趋于平稳，变化幅度可以忽略；通过日气温温差、日太阳辐射总量、风速三个主要气象数据，可以较好的预估CRTS Ⅰ 型板式无砟轨道轨道板一日内的最大正负温度梯度；轨道板的最大正温度梯度与日温差和太阳辐射总量成正比，与风速成反比，轨道板的最大负温度梯度与日温差、太阳辐射量及风速成正比。

Ballastless Track Temperature Field and Track Slab Temperature Gradient Prediction Model in Severe Cold Area

The value range of temperature load of ballastless track structure in severe cold area is a key engineering issue that needs to be solved urgently in track structure design and operations phase. Based on the historical meteorological data of the four major cities of Dalian, Shenyang, Changchun and Harbin in Northeast China, along with the basic thermodynamic principles, a thermodynamic model of CRTS I slab ballastless track-subgrade structure is established to analyze the ballastless track-subgrade structure under severe meteorological conditions. According to the distribution characteristics of the temperature field and the fitting calculation results, a prediction model for the relationship between the maximum positive and negative temperature gradient of the track slab and meteorological data is established, and the most severe temperature gradient value of the track slab in the severe cold region of Northeast China is discussed. The results show that the vertical distribution of the internal temperature of the CRTS I slab ballastless track-subgrade structure is nonlinear. Within the depth of 0.2 m, the daily temperature changes of the track slab and the subgrade are relatively intense, and they are subject to the alternation of positive and negative temperature gradients within a day. Within the depth of 1.4m, the temperature of the roadbed tends to be stable, and the change range can be ignored; Through the three main meteorological data of daily temperature difference, daily total solar radiation and wind speed, the maximum positive and negative temperature gradient of CRTs I slab ballastless track slab in one day can be predicted well. The maximum positive temperature gradient of the track plate is directly proportional to the daily temperature difference and the total solar radiation, and inversely proportional to the wind speed. The maximum negative temperature gradient of the track plate is directly proportional to the daily temperature difference, the solar radiation and the wind speed.