本文選題：紅土　切入點：成因　出處：《昆明理工大學(xué)》2015年碩士論文

【摘要】：紅土以其特殊的物理、水理及力學(xué)性質(zhì)區(qū)別于一般的黏性土,由于經(jīng)濟(jì)的飛速發(fā)展,在紅土分布區(qū)的工程建設(shè)與日俱增,紅土特殊的工程性質(zhì)對工程建筑安全穩(wěn)定影響日益凸顯。昆明長水機場位于滇東高原盆地昆明巖溶高原湖盆亞區(qū),昆明盆地東北部,區(qū)內(nèi)紅土發(fā)育,紅土成因類型及其工程性質(zhì)較為復(fù)雜,對機場各類建筑物安全穩(wěn)定影響較大。由于傳統(tǒng)紅黏土理論存在不足和缺陷,機場巖土工程勘察成果把工程區(qū)砂頁巖和玄武巖等硅酸鹽巖經(jīng)紅土化作用形成的紅土簡單粗糙地分類命名為“紅黏土”,未能客觀真實地反映紅土的成因類型及工程特性,使機場巖土工程勘察成果存在缺陷。紅土特殊的團(tuán)粒結(jié)構(gòu),使其表現(xiàn)出天然密度較小,天然含水量、飽和度、孔隙比較大,液限、塑限高,從而導(dǎo)致紅土在物理、水理性質(zhì)具有軟土的特性,在力學(xué)性質(zhì)方面又表現(xiàn)出砂質(zhì)粉土的特點,使得紅土工程地質(zhì)特性非常特殊。紅土的團(tuán)粒結(jié)構(gòu)是紅土化作用的直接結(jié)果,紅土團(tuán)粒的粒徑大小、含量多少,以及組成團(tuán)粒結(jié)構(gòu)單元體的數(shù)量等是影響紅土特殊工程性質(zhì)的基本因素。由于學(xué)術(shù)界對紅土成因及分類研究存在嚴(yán)重分歧,對紅土粒度成分的分析研究缺乏系統(tǒng)性,現(xiàn)有實驗規(guī)程規(guī)范對紅土粒度成分測試規(guī)定缺乏客觀科學(xué)依據(jù),使對紅土粒度成分的分析結(jié)果離散性太大,毫無規(guī)律可循,更未能準(zhǔn)確地反映紅土的團(tuán)粒粒徑大小、團(tuán)粒數(shù)量及結(jié)構(gòu)單元體含量等。本文按照導(dǎo)師符必昌建立的紅土成因理論所確立的長水機場紅土成因類型,主要對長水機場砂頁巖(ε2d)和玄武巖(P2e)殘積紅土的粒度成分在不同分散劑類型、不同濃度下的粒度成分變化規(guī)律及粒度成分特征值進(jìn)行系統(tǒng)分析研究,客觀揭示各種分散劑對不同紅土類型的作用效果、不同紅土類型粒度成分的差異及主要特征,為進(jìn)一步綜合系統(tǒng)地分析研究紅土的工程地質(zhì)特性奠定基礎(chǔ)。昆明長水機場砂頁巖和玄武巖經(jīng)紅土化作用形成了相應(yīng)的殘積紅土,根據(jù)紅土化作用程度可把殘積紅土劃分成典型紅土、塊狀紅土、散粒紅土。寒武系中統(tǒng)陡坡寺組砂頁巖殘積紅土因較強侵蝕作用,只保留了塊狀紅土、散粒紅土。而二疊系中統(tǒng)峨眉山組玄武巖殘積紅土剖面保存較好,其典型紅土、塊狀紅土、散粒紅土均得以保存。本文采用4種分散劑在不同濃度條件下分別對上述5類土樣進(jìn)行粒度成分的綜合試驗研究。本文對上述5類紅土樣品的粒度成分試驗進(jìn)行總結(jié)分析得出：(1)在未加分散劑條件下,砂頁巖和玄武巖各自的殘積紅土主要集中在粉粒組,表明塊狀紅土和散粒紅土土體顆粒極不均一,以粉粒團(tuán)粒體為主的狀態(tài)存在,不同紅土化作用階段形成的殘積紅土在分散效果方面各自具有共性又具有特性；(2)雙氧水用于去除含有機質(zhì)土中的有機質(zhì)時有一定效果,但單獨使用時效果不佳；選擇單獨使用的分散劑時,應(yīng)該逐步放棄使用氨水和雙氧水,但可以考慮結(jié)合其它分散劑共同使用；(3)此4類分散劑普遍存在一個共同點,即在一定范圍內(nèi)分散效果隨著分散劑濃度增加而加強,當(dāng)濃度到達(dá)某個數(shù)值以后分散效果發(fā)生質(zhì)變,達(dá)到最佳分散區(qū)間及最佳分散值,隨后分散效果逐步下降；(4)同一土樣采用不同的分散劑及濃度值,所得到的粒組含量受到很大影響,可能得出不同的定名,致使紅土的定名和工程性質(zhì)與其實際狀況存在一定差異,分散劑的種類及其濃度值對粒度成分試驗至關(guān)重要；(5)砂頁巖殘積紅土及玄武巖殘積紅土的團(tuán)粒結(jié)構(gòu)實質(zhì)就是由膠粒為主膠結(jié)而成的粉粒團(tuán)體,具有假集合體及遇水穩(wěn)定的抗水集合體的特性；(6)散粒紅土建議使用3%-5%六偏磷酸鈉作為分散劑,典型和塊狀紅土建議使用6%-8%六偏磷酸鈉作為分散劑分散效果更佳；(7)規(guī)范建議的分散劑的濃度值,測試結(jié)果大多沒有達(dá)到峰值,說明紅土作為特殊黏性土在粒度成分方面具有特殊性,區(qū)別于一般黏性土,應(yīng)給與區(qū)別對待。
[Abstract]:The red soil is distinguished from the general clay by its special physical , water and mechanical properties . Due to the rapid development of the economy , the engineering construction in the red soil distribution area is increasing day by day . The special engineering property of the laterite is more and more obvious to the construction safety and stability of the project . In this paper , a systematic analysis of the characteristics of red earth ' s grain size composition is carried out in this paper . The results show that the characteristics of the red earth ' s grain size , the size and the content of the granular components of the red soil are very special .
( 2 ) When the hydrogen peroxide is used to remove organic matter contained in organic matter , it has certain effect , but the effect is not good when used alone ;
When the dispersant used alone is selected , ammonia water and hydrogen peroxide should be gradually discarded , but it can be used in combination with other dispersants ;
( 3 ) There is a common point in the 4 kinds of dispersing agents , that is , the dispersion effect is enhanced with the increase of the concentration of the dispersant in a certain range . When the concentration reaches a certain value , the dispersion effect is changed , the optimal dispersion range and the optimal dispersion value are achieved , and then the dispersion effect is gradually decreased ;
( 4 ) In the same soil sample , different dispersing agents and concentration values are adopted , the content of the obtained grain groups is greatly influenced , and different orders can be obtained , so that the definite name and engineering property of the red soil are different from the actual conditions , and the type and the concentration value of the dispersing agent are very important to the particle size component test ;
( 5 ) The grain structure of the eluvial red soil and the basalt residual red soil of the sand shale is basically a grain group composed of colloidal particles , which has the characteristics of a false aggregate and an anti - water aggregate stable in water ;
( 6 ) It is suggested that using 3 % -5 % sodium hexaaluminate as the dispersing agent , and 6 % -8 % sodium hexaaluminate can be used as the dispersing agent to disperse the red soil .
( 7 ) According to the concentration value of the dispersant in the specification , most of the test results do not reach the peak value , indicating that the red soil has special characteristics in the aspect of particle size composition as a special clay , and is different from the general clay , and should be treated differently .

【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P642.132

【參考文獻(xiàn)】

相關(guān)期刊論文 前9條

1 朱顯謨;;中國南方的紅土與紅色風(fēng)化殼[J];第四紀(jì)研究;1993年01期

2 馮金良;粘性土（紅土）中游離氧化鐵含量對其工程地質(zhì)性質(zhì)的影響[J];工程地質(zhì)學(xué)報;1996年01期

3 廖義玲;朱要強;趙坤;賀s，

本文編號：1683838