水分条件对季节性冻土区原状土冻胀特性影响的试验研究  

Experimental study on the influence of moisture conditions on the frost heave characteristics of undisturbed soil in seasonally frozen soil

作　　者：刘建宇 王沛 黄伟 王刚[1] 李兆宇 LIU Jianyu;WANG Pei;HUANG Wei;WANG Gang;LI Zhaoyu(Mudanjiang Comprehensive Survey Center for Natural Resources,China Geological Survey,Heilongjiang,Mudanjiang 157021,China;Heilongjiang Insititute of Water Resources Rwsearch,Harbin 150080,China)

机构地区：[1]中国地质调查局牡丹江自然资源综合调查中心,黑龙江牡丹江157021 [2]黑龙江省水利科学研究院,哈尔滨150080

出　　处：《华北地质》2025年第1期87-94,共8页North China Geology

基　　金：中国地质调查局项目:“东北边境珲春—东宁地区综合地质调查项目”(DD20208014、ZD20220402)。

摘　　要：[研究目的]冻胀是季节性冻土区路基工程普遍存在的危害,系统地研究季冻区典型土类的冻胀规律可有效地为冻胀防治提供科学支持。[研究方法]本文基于原位钻探采取未扰动原状粉质黏土为研究对象,采用多通道光纤光栅测温系统监测冻结封面移动,采用单因素冻胀试验设计方法,开展﹣5℃、﹣15℃、﹣25℃温度梯度下封闭/开放系统冻结对比试验,探讨了不同水分条件对冻胀的特性,筛选了更大范围的原状土样的天然初始含水率,对冻胀率变化趋势进行了整体把握,主要结论补充完善了前人的研究结果,在封闭系统条件下变化趋势基本相同,但在开放系统下冻胀率的在变化趋势上、变化界限点和极值点上存在差异,同时构建了关于两种因素影响下的冻胀预测方程。[研究结果]结果表明:初始含水率和补水条件都对冻胀率有显著影响,封闭系统条件下,土体随着初始含水率的增大,冻胀率呈现先增大后趋于稳定的变化规律,开放系统呈现抛物线响应,不同补水系统条件下冻胀率相差2~5倍,决定原状粉质粘土的冻胀特性内在本质因素是其结构性。[结论]提出临界含水率(开放系统24%、封闭系统31%)控制指标与冻胀预测方程,可为地下水活动频繁的季节性冻土区工程中粉质黏土冻胀防治与冻胀率预测提供一定参考。[Objective]Frost heave is a common disease in the subgrade engineering of seasonal frozen soil areas.The aim of this paper is to systematically understand the frost heave laws of typical soil types in the seasonally frozen soil area.[Methods]This paper takes undisturbed natural silt clay obtained from in-situ drilling as the research object.A multi-channel fiber Bragg grating temperature measurement system is used to monitor the movement of the freezing front.A single-factor frost heave test is adopted to conduct closed/open system freezing comparison tests at temperature gradients of﹣5°C,﹣15°C,and﹣25°C.The characteristics of frost heave under different moisture conditions are explored.A wider range of natural initial moisture contents of undisturbed soil samples is selected to grasp the overall trend of rate changes frost heave.The main conclusions supplement and improve the previous research results.Under the closed system conditions,the change trends are basically the same,but under open system conditions,there are differences in the change trends,change boundary points,and extreme points of the frost heave rate.At the same time,a frost heave prediction equation under the influence of two factors is constructed.[Results]The results show that both the initial moisture content and the water replenishment conditions have a significant impact on the frost heave rate.Under closed system conditions,the frost heave rate of the soil increases first and then tends to be stable as the initial moisture content increases.Under open system conditions,it shows a parabolic response.The frost heave rates under different water replenishment system conditions differ by 2 to 5 times.The intrinsic factor determining the frost heave characteristics of natural silt clay is its structure.[Conclusions]The critical moisture content control indicators(24%for open system and 31%for closed system)and the frost heave prediction equation are proposed,which can provide certain references for the prevention and prediction of frost h

关 键 词：季冻土 原状土 冻胀试验 开放系统 冻胀率 

分 类 号：TU445[建筑科学—岩土工程]