【摘要】：紅層與黃土在中國西部地區(qū)廣泛分布。黃土下伏的古風(fēng)化紅層基巖往往構(gòu)成黃土滑坡的底界,是黃土滑坡形成的控制性邊界條件。與古風(fēng)化泥巖相關(guān)的滑坡在區(qū)內(nèi)頻頻發(fā)生,造成了嚴(yán)重的人員傷亡和經(jīng)濟損失,極大地制約了當(dāng)?shù)亟?jīng)濟的正常發(fā)展。因此,認(rèn)清泥巖的風(fēng)化特點和工程屬性,對區(qū)內(nèi)滑坡的研究和防治都具有重要意義。本文以蘭州及其周邊地區(qū)白堊系古風(fēng)化紅層泥巖為對象,在詳細(xì)的野外地質(zhì)調(diào)查基礎(chǔ)上,選擇了9個階地卵石層下伏的古風(fēng)化紅層剖面進(jìn)行了硬度試驗、回彈試驗和磁化率試驗,同時在剖面上取樣并進(jìn)行了室內(nèi)崩解試驗,根據(jù)試驗結(jié)果對卵石層下lm范圍內(nèi)的紅層泥巖進(jìn)行了風(fēng)化帶劃分,綜合研究了古風(fēng)化泥巖的崩解性和水巖相互作用,討論了古風(fēng)化泥巖對黃土滑坡的控制作用。主要結(jié)論如下：(1)硬度試驗、回彈試驗和磁化率試驗結(jié)果均顯示出相同的規(guī)律,即在剖面表層其值較小,隨著深度的增加其值增大。變異系數(shù)也呈現(xiàn)出明顯的變化規(guī)律,泥質(zhì)砂巖剖面上在卵石層下10-30cm處發(fā)生突變,泥巖剖面上在卵石層下50cm處發(fā)生突變,且均從0.6左右突變至0.7左右。(2)對9個巖石剖面進(jìn)行磁化率試驗,發(fā)現(xiàn)各剖面均呈現(xiàn)出表層磁化率較大,隨著深度的增加磁化率值有所減小的趨勢。其中4個砂巖剖面表層10cm到20cm磁化率值較大,20cm以下磁化率較�。黄渌�5個泥巖剖面為表層10cm到30cm磁化率值較大,其下磁化率值較小,且有上下波動現(xiàn)象。表層磁化率升高的原因主要為風(fēng)化作用和成壤作用。(3)崩解試驗獲取的巖石崩解性變化特征為：卵石層以下0-30cm的巖石崩解性很強,崩解度幾乎接近100%；30-50cm的巖石崩解性較強；50-100cm崩解性較弱,其中90-100cm崩解性最弱,崩解度還不到50%。(4)對試驗結(jié)果進(jìn)行綜合分析得到黃土層底部白堊系紅層泥巖古風(fēng)化殼表面強風(fēng)化層深度較大,達(dá)到卵石層下30-50cm范圍,相對來說泥質(zhì)砂巖剖面強風(fēng)化層深度較小,處于卵石層下20-30cm的范圍內(nèi)。結(jié)合泥巖崩解過程中水溶液EC、TDS和pH值的變化規(guī)律,認(rèn)為在地下水作用下強風(fēng)化巖石中的可溶鹽損失嚴(yán)重,其溶解到地下水中后使地下水堿性增強,加快了地下水對巖石膠結(jié)物的破壞,導(dǎo)致巖石抗剪強度持續(xù)降低,使得黃土底部強風(fēng)化泥巖容易發(fā)育成黃土滑坡滑動面。
[Abstract]:Red beds and loess are widely distributed in western China. The paleo-weathered red bed bedrock under loess often forms the bottom boundary of loess landslide and is the controlling boundary condition for the formation of loess landslide. Landslides associated with paleo-weathered mudstone occur frequently in the area, resulting in serious casualties and economic losses, which greatly restrict the normal development of local economy. Therefore, it is of great significance to recognize the weathering characteristics and engineering properties of mudstone for the study and prevention of landslide in this area. Taking the Cretaceous paleo-weathered red layer mudstone in Lanzhou and its surrounding area as the object, on the basis of detailed field geological investigation, the hardness tests of the paleo-weathered red bed section of 9 terrace pebbles are carried out. The springback test and magnetic susceptibility test were carried out. At the same time, samples were taken from the section and the indoor disintegration test was carried out. According to the test results, the weathering zones of red mudstone in the range of lm under the pebble layer were divided into weathering zones. The disintegration of paleo-weathered mudstone and the interaction of water and rock are studied synthetically, and the control effect of paleo-weathered mudstone on loess landslide is discussed. The main conclusions are as follows: (1) the results of hardness test, springback test and magnetic susceptibility test all show the same rule, that is, the value of the surface layer of the section is smaller, and the value increases with the increase of depth. The coefficient of variation also showed an obvious variation law. In the shaly sandstone section there was a mutation at 10-30cm under the pebble layer, and in the mudstone section there was a mutation at the 50cm under the pebble layer. All of them have mutated from 0.6 to 0.7. (2) the susceptibility tests of 9 rock sections show that the surface susceptibility of each profile is larger, and the value of susceptibility decreases with the increase of depth. The surface 10cm to 20cm susceptibility of four sandstone sections is larger than that below 20cm, while the other five mudstone sections are the surface layer 10cm to 30cm magnetic susceptibility value is larger, its lower magnetic susceptibility value is smaller, and has the phenomenon of fluctuating up and down. The main reasons for the increase of surface magnetic susceptibility are weathering and soil formation. (3) the characteristics of rock disintegration obtained by disintegration test are as follows: the rock disintegrating property of 0-30cm below the pebble layer is very strong, and the disintegration degree is almost close to 100g; The rock disintegration of 30-50cm is strong; 50-100cm disintegration is weak, among which 90-100cm disintegration is the weakest, and the disintegration degree is less than 50%. (4) it is found that the strong weathering layer on the surface of the Cretaceous red mudstone paleo-weathering crust at the bottom of the loess soil layer is deep, and the disintegration degree is less than 50%. To reach the 30-50cm range under pebble, the depth of strongly weathered layer in shaly sandstone profile is relatively small, which is within the range of 20-30cm under pebbles. Combined with the variation of EC,TDS and pH values in aqueous solution during mudstone disintegration, it is considered that the loss of soluble salt in strongly weathered rock under the action of groundwater is serious, and the alkali of groundwater is enhanced when dissolved into groundwater. It accelerates the destruction of rock cement by underground water, which leads to the continuous decrease of shear strength of rock, which makes the strongly weathered mudstone at the bottom of loess easily develop into the sliding surface of loess landslide.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P534.53;P512.13

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 張立新;;古風(fēng)化殼的特征及工程實例[J];鐵道勘察;2008年05期

2 廖士范;;關(guān)于風(fēng)化殼建造、古風(fēng)化殼建造及其形成機理問題[J];巖相古地理;1993年05期

3 李中明;趙建敏;馮輝;李偉;焦贊超;岳國利;;河南省郁山古風(fēng)化殼型稀土礦層的首次發(fā)現(xiàn)及意義[J];礦產(chǎn)與地質(zhì);2007年02期

4 馬振芳;鄂爾多斯盆地中部古風(fēng)化殼儲層特征[J];天然氣地球科學(xué);1994年06期

5 李景陽,朱立軍;論碳酸鹽巖現(xiàn)代風(fēng)化殼和古風(fēng)化殼[J];中國巖溶;2004年01期

6 唐時嘉;四川盆地紅層的古風(fēng)化殼[J];土壤學(xué)報;1986年02期

7 劉文凱;遵義鋁土礦的古風(fēng)化殼分帶模式[J];貴州地質(zhì);1993年04期

8 肖東佑;;某水利水電工程中古風(fēng)化殼的基本特性及其對工程的影響[J];資源環(huán)境與工程;2012年05期

9 張占君;阿爾泰山古風(fēng)化殼及其找礦意義[J];干旱區(qū)地理;1991年03期

10 唐時嘉;四川盆地紅層古風(fēng)化殼及其利用特點[J];西南師范學(xué)院學(xué)報(自然科學(xué)版);1985年03期

相關(guān)會議論文 前5條

1 李景陽;朱立軍;;論碳酸鹽巖現(xiàn)代風(fēng)化殼和古風(fēng)化殼[A];貴州省科學(xué)技術(shù)優(yōu)秀學(xué)術(shù)論文集（2004年度）[C];2004年

2 李景陽;朱立軍;;論碳酸鹽巖現(xiàn)代風(fēng)化殼和古風(fēng)化殼[A];貴州省自然科學(xué)優(yōu)秀學(xué)術(shù)論文集[C];2005年

3 沈德麒;孫恭安;陳耀欽;;河南許昌—舞陽地區(qū)古風(fēng)化殼[A];中國地質(zhì)科學(xué)院宜昌地質(zhì)礦產(chǎn)研究所文集（2）[C];1981年

4 樊金生;郭文波;王美丁;王輝;;古風(fēng)化殼沉積型鋁土礦物探異常模式及系列方案[A];陜西地球物理文集（十）--資源與災(zāi)害地球物理[C];2011年

5 張海;何明友;郭佩佩;李媛媛;周光紅;;貴州西部二疊系玄武巖古風(fēng)化殼型鐵多金屬礦床演化特征研究[A];中國礦物巖石地球化學(xué)學(xué)會第14屆學(xué)術(shù)年會論文摘要專輯[C];2013年

相關(guān)碩士學(xué)位論文 前2條

1 周建基;蘭州地區(qū)白堊系紅層泥巖的古風(fēng)化殼特征研究[D];蘭州大學(xué);2015年

2 賈雪梅;黑方臺紅層泥巖的風(fēng)化作用及其古風(fēng)化殼特征[D];蘭州大學(xué);2014年

，

本文編號：2397767