季节性冻土区毛细导水土工材料抑制路基土冻胀破坏效果试验研究

 2022-09-04 08:09

论文总字数:24568字

摘 要

冻土是指零摄氏度以下,并含有冰的各种岩石和土壤。我国是世界第三大冻土国,季节性冻土区面积大约513.7万平方千米,占国土面积的53.5%。季节性冻土的冻胀性、融沉性等特性对工程影响重大。

目前常用的解决破坏的处理方法水沟等,以上措施对,但存在一些不足,有些方法费时、费力、费钱,不同程度地限制交通的畅通性。有些措施多次冻融循环后效果大幅下降,稳定性差。本文提出的是通过毛细导水土工材料将路基土中的水排出,降低路基土含水量,从而起到研究毛细导水土工材料对抑制季节性冻土区路基土冻胀破坏的作用。

本文在研究国内外研究现状的基础上,以商用高岭土为研究对象,通过对使用毛细导水土工材料处理过的不同含水量高岭土样进行排水试验和冻融试验,研究在季节性冻土区毛细导水土工材料抑制路基土冻胀破坏研究的效果,主要成果如下:

(1)在季节性冻土区毛细导水土工材料抑制路基土的冻胀破坏的作用机理是通过将路基土中的水分通过毛细导水土工材料排出,降低路基土中水分含量,从而起到抑制路基土冻胀破坏的效果。

(2)通过对不同初始含水量的试样在竖向冻胀融沉率,径向冻胀融沉率和体积冻胀融沉率上的比较,发现毛细导水土工材料主要是体现在对路基土的的降低,而对于路基土初始的冻胀量变化速率没有太大影响。

(3)通过排水试验研究了两种毛细导水土工材料的吸水排水性能,发现Dri-Release材料的排水性能优于Coolmax材料。

关键词:季节性冻土区、路基土、毛细导水土工材料、排水量、冻胀量

Abstract

Frozen soil is below zero degrees Celsius and contains ice for various rocks and soil. China is the world's third largest frozen soil, seasonal frozen soil area is about 513.7 million square kilometers, accounting for 53.5% of the land area, the southern boundary from Yunnan Zhang Feng, east to Kunming, Guiyang, around the northern edge of the Sichuan Basin , to Changsha, Anqing, Hangzhou area. Seasonal frozen soil frost heretization, melting and other characteristics have significant impact of the project.

At present, the commonly used measures to solve the frost heave destruction of seasonal frozen soil are the method of replacing the subgrade soil, laying geotextiles and setting the drains. The above measures play a certain role in the prevention and improvement of road flood damage, but there are some shortcomings. Measures after the freeze-thaw cycle after the effect of a substantial decline, poor stability, some methods time-consuming, laborious, costly, varying degrees of restrictions on the smooth flow of traffic. In this paper, it is proposed that the water in the soil is drained and the water content of the subgrade soil is reduced by the wicking geotextile material,geotextile on the frost heave damage of the subgrade soil.

This paper is based on the research status quo at home and abroad. In this paper, the commercial kaolin was used as the research object, and the different water content kaolin samples were treated by capillary water and geothermal materials. This paper studies the effect of capillary soil geotextile on the frost heave damage of subgrade soil in seasonal frozen soil area. The main results are as follow:

(1)The mechanism of frost heaving and destruction of geotextile soil in seasonal frozen soil is to reduce the moisture content in the subgrade soil by discharging the moisture in the subgrade soil through the capillary soil. So it can inhibit the embankment soil frost heave damage effect.

(2)The comparison of the samples with different initial water content in the vertical frost heaving and thawing rate, the radial frost heave rate and . We can find that the inhibitory effect of capillary soil geotextile on the freezing and thawing failure of the subgrade soil is mainly reflected in the reduction of the final frost heave amount of the subgrade soil. And the rate of change in the initial frost heave amount of the subgrade soil is not much affected.

(3) The water and drainage performance of two kinds of capillary soils were studied by drainage test. It was found that the drainage performance of the Dri-Release material was slightly stronger than that of the Coolmax material.

Keywords:seasonal frozen soil region,subgrade soil,wicking geotextile, drainage quality,frost-heave capacity.

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 研究背景和研究意义 1

1.2 国内外研究现状 2

1.2.1国外研究现状 2

1.2.2国内研究现状 3

1.3 存在问题及本文主要研究内容 4

1.3.1 存在的主要问题 4

1.3.2 本文研究主要内容 4

1.4 研究技术路线图 4

第二章 试验内容与方法 6

2.1 试验材料 6

2.1.1商业高岭土 6

2.1.2毛细导水土工材料 7

2.2 试验内容与方案 7

2.2.1土柱试样制备方法 7

2.2.2土柱预排水试验 11

2.2.2冻融试验 11

2.3 本章小结 11

第三章 毛细导水土工材料对路基土的排水性能研究 13

3.1 引言 13

3.2 排水试验环境条件 13

3.3 毛细导水土工材料包裹侧面试样排水结果分析 14

3.3.1Coolmax材料排水量分析 14

3.3.2Dri-Release材料排水量分析 17

3.3.3Coolmax材料和Dri-Release材料排水性能对比 19

3.4 在试样中均匀铺设两层毛细导水土工材料试样排水结果分析 22

3.4.1Coolmax材料排水量分析 22

3.4.2 Dri-Release材料排水量图 26

3.5 本章小结 28

第四章 毛细导水材料抑制土样冻融效果研究 30

4.1 引言 30

4.2 试验过程中试样变化现象 30

4.3 毛细导水土工材料包裹侧面试样冻胀融沉率分析 32

4.3.1Coolmax材料处理的试样冻胀融沉率分析 32

4.3.2Dri-Release材料处理的试样冻胀融沉率分析 35

4.4 毛细导水土工材料埋藏在其中的试样冻胀融沉率分析 38

4.4.1 Coolmax材料处理的试样冻胀融沉率分析 38

4.4.2 Dri-Release材料处理的试样冻胀融沉率分析 41

4.5 本章小结 44

第五章 结论与展望 46

5.1 结论 46

5.2 展望 46

参考文献 48

致 谢 50

绪论

研究背景和研究意义

冻土是指。一以及多年冻土[1]。地球上多年冻土,季节冻土和,其中,多年冻土面积占陆地面积的25%。自地表面至冻结层底面的厚度称冻结深度。我国是世界第三大冻土国,其中,;其中多年冻土主要分布于,并零星分布在季节冻土区内的一些高原上,总面积约206万平方千米,占全国面积的21.5%[2]。季节性冻土是受季节性的影响,,占国土面积的53.5%,其南界西从缘,到长沙、安庆、杭州一带。季节冻结深度在可超过3米,往南随纬度降低而减少[3]。季节性冻土的冻胀性、融沉性等特性对工程影响重大。

季节性冻土路性。土体的热状况、水分状况及由此引起的冻胀与融化是致使道路发生冻胀、翻浆等病害的主要因素[4]。水分是作为温度及变形的载体,是产生冻胀与融沉的前提:一方面力,会引起水分的不均匀集聚;另一方面,随着温度的降低或升高,土体中的水分也会随之,引起土体发生沉,当土体中的应力和变形超过其允许范围时,便产生路基路面的病害。由此可见引起冻土地区路问题[5]。因此是保证冻土路基稳定的重要措施,是减的关键所在。为了保证有效,铁路部门每年需花费大和维修[6]

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