基于GM(1,1)模型的高速铁路沉降分析预测

GM(1,1)模型是变形监测中常用的一种预测模型,针对复杂的高速铁路累计沉降数据序列,采用传统GM(1,1)模型、时变参数GM(1,1)模型和新时变参数GM(1,1)模型进行分析预测,通过对比几种模型的拟合预测精度发现,新时变参数GM(1,1)模型能显著提高拟合预测精度,适用于高速铁路沉降分析和预测。研究结果可为高速铁路的沉降监测提供一定的参考价值。

高速铁路线下工程沉降观测评估项目案例分析

对高速铁路线下观测沉降观测评估项目中的几个工作重点进行了详细描述,阐述了外业检查及内业数据检查的重要性,对保证工程质量、提高作业效率、消除工程隐患具有积极意义。

高铁路基沉降监测的布设方案和技术应用研究

本文结合路基沉降在高速铁路工程建设中所起的必要作用,对高速铁路路基沉降观测的布设方案和技术应用进行具体的阐述,详细介绍了路基沉降观测的技术方法及技术要点,以保证施工工程的质量、安全运营及延长工程的寿命使用,为在以后路基沉降工程的测量工作中提供重要的参考依据。

新型沉降板在高铁施工中的应用研究

高速铁路路基用工后沉降对路基沉降变形进行严格控制,老式沉降板是最常用的手段,但其存在影响填土施工和在使用中容易被破坏并难以恢复的缺点,新型沉降板的设计理论上改掉了这些缺点,但是缺少在具体工程中的应用研究。本文结合工程试验,收集在实际工程施工使用中遇到的各种问题,验证新型沉降板应用效果,积累施工工艺经验,促使其在高铁施工中的推广。

A computational method for post-construction settlement of high-speed railway bridge pile foundation considering soil creep effect

Based on reasonable assumptions that simplified the calculational model,a simple and practical method was proposed to calculate the post-construction settlement of high-speed railway bridge pile foundation by using the Mesri creep model to describe the soil characteristics and the Mindlin-Geddes method considering pile diameter to calculate the vertical additional stress of pile bottom.A program named CPPS was designed for this method to calculate the post-construction settlement of a high-speed railway bridge pile foundation.The result indicates that the post-construction settlement in 100 years meets the requirements of the engineering specifications,and in the first two decades,the post-construction settlement is about 80% of its total settlement,while the settlement in the rest eighty years tends to be stable.Compared with the measured settlement after laying railway tracks,the calculational result is closed to that of the measured,and the results are conservative with a high computational accuracy.It is noted that the method can be used to calculate the post-construction settlement for the preliminary design of high-speed railway bridge pile foundation.

Long-term settlement prediction of high-speed railway bridge pile foundation

The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading.Moreover,the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform.The three-dimensional composite analysis method of bridge pile group was improved,where the actual load conditions of pile foundation could be simulated,and the consolidation characteristics of soil layers beneath pile were also taken into account.Eventually,a corresponding program named LTPGS was developed to improve the calculation efficiency.The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated,and a close agreement is obtained.The error between computed and measured results is less than 1 mm,and it gradually reduces with time.It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.

Influence and Control Strategy for Local Settlement for High-Speed Railway Infrastructure

This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.

Analysis of nonlinear settlement for an unsaturated soil under stage continuous loading

A new approach was proposed to describe settlement behavior of an unsaturated soil with subgrade filling for high-speed railway. Firstly, based on Terzaghi consolidation theory, equations considering the variation coefficient of consolidation with void ratio and saturation for consolidation of an unsaturated soil under stage continuous loading were derived, and according to analytical solutions of equations, a formula for settlement computation under stage continuous loading was obtained. Then, combined with the width-to-height ratio of subgrade to compute ground reaction, and by means of in-situ plate loading curves, a correctional approach was presented for the analysis of nonlinear settlement of foundation. Also, the comparison between calculated and measured loadsettlement behavior for an unsaturated soil in Qingdao-Ji'nan high-speed railway was given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to predict the settlement of an unsaturated soil foundation under stage continuous loading in engineering design.

Observation and evaluation of bridge settlement in Beijing—Tianjin intercity railway

Specific requirements and methods of settlement monitoring which were used in bridge of unballasted track passenger dedicated line or high-speed railway are introduced systematically,and mathematical model and determinant conditions of settlement were proposed simultaneously,taking Beijing—Tianjin intercity railway as an example.