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1.
用蒙脱石层间水化状态修正了土壤孔隙率的计算方程,以此建立蒙脱石层间脱水作用所产生的次要地面沉降量的数学表达式,并对无锡石塘湾地面沉降区进行了模拟计算。无锡石塘湾地区因蒙脱石层间释水所产生的次要地面沉降量为39.02 cm,占整个沉降量的19.51%,人工回灌后,次要地面沉降量变为36.04 cm,占整个沉降量的18.02%,表明人工回灌是阻止地面继续沉降的有效措施之一。计算表明,如果蒙脱石残余层间水全部释出,那么无锡石塘湾地区可能有117.39 cm的地面沉降空间。虽然这一结果在真实的外界环境下不可能实现,但对下一步就地面沉降灾害的治理、防治具有一定的警示作用。蒙脱石层间脱水作用及其对地面沉降影响的研究,可能对地面沉降趋势的预测具有启示作用。  相似文献   

2.
蒙脱石脱水作用与地面沉降关系的研究展望   总被引:7,自引:0,他引:7  
粘土矿物在地面沉降中的作用、粘土矿物的脱水作用对地面沉降的影响等日益成为评价和防治地质、工程、水文、环境等问题的关键,也一直是相关领域的研究难题而逐渐引起高度重视。本文回顾了蒙脱石层间水性质、层间水化膨胀和脱水收缩的影响因素,提出蒙脱石层间的固溶体特征,在总结蒙脱石脱水作用与地面沉降关系研究成果的基础上,提出了用蒙脱石脱水作用研究地面沉降的思路。最后讨论了用蒙脱石的脱水作用研究地面滞后沉降及沉降趋势预测的可能性。  相似文献   

3.
地下水超采条件下蒙脱石的脱水作用对地面沉降的影响   总被引:3,自引:0,他引:3  
据统计 ,80 %的地面沉降是由地下水超采引起的。已有的计算模型 ,多数是针对土壤的主要压实作用 ,而涉及因地下水超采造成粘性土结构性调整 ,尤其是导致蒙脱石层间水释出的次要压密效应 ,并用于潜在的地面沉降的分析和研究则较少。大量的测试资料表明 ,第四纪土壤层中蒙脱石 (0 0 1)底面间距的状态有~ 1,~ 1.2 5 ,~ 1.5 5和~ 1.85nm。~ 1nm蒙脱石层间区域几乎完全不含水分子 ,且层间区域的空间大小几乎等于 0 ;~ 1.2 5nm层间区域含水量为~ 10 % (质量分数 ) ;~ 1.5 5为~ 2 0 % (质量分数 ) ;~ 1.85则为~ 2 5 % (质量分数 )。研究…  相似文献   

4.
蒙脱石的成岩演变与石油的初次运移   总被引:1,自引:1,他引:1  
王行信 《沉积学报》1985,3(1):81-91
自从鲍尔斯提出成岩过程中蒙脱石脱水对油气初次运移的重要性以后,许多学者对成岩过程中蒙脱石的脱水反应特征及在油气初次运移中的意义进行了研究和讨论。一般认为成岩过程中蒙脱石的脱水为石油初次运移创造了下列有利条件: 1.提供水介质来源; 2.重新产生孔隙度; 3.促进泥岩异常高压带的形成; 4.由于蒙脱石层间水的加入,提高了烃类和脂肪酸在水中的溶解度,促进了石油的运移。 成岩过程中蒙脱石析出层间水只是蒙脱石成岩演变的一个方面,如果仅以脱水量的多少和烃类在水中溶解度的概念来评价蒙脱石的成岩演变对油气运移的影响,这显然是不够的。 关于松辽盆地白垩系泥岩粘土矿物成岩演变特征与有机变质作用和油气分布的关系,可参阅作者的有关论文[1][2],这里不再赘述。  相似文献   

5.
埋藏条件下蒙脱石层间水的稳定性   总被引:3,自引:0,他引:3  
蒙脱石族矿物广泛存在于地表各种环境中,其层间结构的稳定性对各种表生地质作用的发生和过程起着重要作用。在砂岩成岩作用中,蒙脱石族矿物的脱水作用改变了砂岩孔隙流体的量和成分,同时也降低了油气储蓄层的孔隙度和渗透性。泥、页岩中由于蒙脱石族矿物的脱水作用,在...  相似文献   

6.
为了准确分析建筑荷载和地下水开采对地面沉降的影响,为吴江盛泽地区科学防控地面沉降提供决策依据,基于比奥固结和地下水渗流理论,建立了建筑荷载和地下水开采与地面沉降三维全耦合有限元数值模型,分别模拟预测了在建筑荷载单独作用、地下水开采单独作用及建筑荷载和地下水开采叠加作用三种情况下,2015-09-01—2030-08-31盛泽地区逐年地面沉降变化趋势。结果表明,建筑荷载对盛泽地区地面沉降的影响大于地下水开采。第Ⅰ黏性土弱含水层和第I承压含水层分别为建筑荷载和地下水开采单独作用下的主压缩层,单层压缩量占比分别为43.04%和54.06%;第Ⅰ承压含水层及其上覆第Ⅰ黏性土弱含水层是二者叠加作用引发土体变形的主压缩层,其压缩量之和占总压缩量的71.30%。建筑荷载和地下水开采单独作用下引发的地面沉降量的线性叠加之和大于二者叠加作用下引发的地面沉降量,建筑荷载和地下水开采叠加作用引发的地面沉降具有耦合效应。  相似文献   

7.
钙钠离子对蒙脱石脱水特性的影响   总被引:2,自引:1,他引:2  
蒙脱石的脱水特性通常是指它所含水分(包括吸附水、层间或OH结构水)的损失特性,如水分失去量、脱水速率和脱水温度等。这些特性不仅与蒙脱石矿物本身的成分有关,而且与其所吸附的阳离子密切相关。膨润土是以蒙脱石类矿物为主要成分的粘土,它的物理化学性质主要由其中的蒙脱石所决定。蒙脱石吸附的钙、钠离子又是决定膨润土工业使用价  相似文献   

8.
在水体系中,蒙脱石矿物表面结合水膜厚度大小,取决于矿物层间阳离子及矿物的晶体化学特征.当层间阳离子种类相同时,首先取决于水与矿物结构参数的不适应程度.结合水膜厚度,影响蒙脱石层间阳离子在土—水体系中的电导率.本文通过对不同地区、不同类型蒙脱石—水体系电导率测定,讨论水与蒙脱石晶胞参数不适应度对体系电导率的影响规律.  相似文献   

9.
蒙脱石伊利石化过程中伊-蒙混层形成的Gibbs自由能   总被引:3,自引:0,他引:3  
采用Vieillard(2000)提出的计算含水粘土矿物形成的Gibbs自由能的方法,对热液蚀变作用下蒙脱石向伊利石转变过程中伊利石.蒙脱石混层形成的Gibbs自由能进行了计算。根据伊利石-蒙脱石混层的化学成分,详细计算了一个端元伊利石样品形成的Gibbs自由能,其值为-5401.36kJ/mol。该值与已给出的天然伊利石和理想伊利石形成的Gibbs自由能非常相近,表明Vieillard(2000)的方法对计算伊利石-蒙脱石混层形成的Gibbs自由能是可行的。伊利石-蒙脱石形成的Gibbs自由能可进一步用于计算因地下水过量开采而产生的地面沉降的量。  相似文献   

10.
北京区域地面沉降呈快速发展趋势,局部最大形变速率超过13cm/a,严重威胁城市安全。掌握地下水开采条件下的分层地面沉降特征,是定量揭示地面沉降机理和缓解沉降灾害的前提。以北京最大的地面沉降区温榆河冲洪积扇地区的八仙庄沉降区为研究对象,分析了该地区地下水开采、地下水位动态特征与分层压缩量的关系,基于分层沉降数据得出该地区土体释水形变以浅部地层、深部地层的弹性形变以及中深部地层的弹塑性形变为主,并从地层条件、固结历史和物理力学性质方面对压缩特性的影响因素进行了分析,得出以地面沉降为约束条件的地下水开采主要调控层分布。  相似文献   

11.
Traditionally, land subsidence that results from groundwater over-pumping has often been described by the theory of consolidation. The mechanism of land subsidence due to the dehydration of clay minerals is not well addressed. A model of the “hydration state of smectite”, and a “solid solution model of smectite dehydration”, incorporating a thermodynamic solid solution model and laboratory results concerning clay-water systems of swelling pressure, hydration state and basal spacing in smectite interlayer, are employed to examine the effect of the release of water from the smectite interlayer on land subsidence in the coastal area of the Chou-Shui River alluvial fan and the Yun Lin offshore industrial infrastructure complex in Taiwan. The results indicate that 9.56–22.80% of the total cumulative land subsidence to a depth of 300 m is consistent with smectite dehydration following the over-pumping of groundwater. This dehydration-related land subsidence occurred to a depth of 0–60 m, with subsidence due to smectite dehydration accounting for 6.20–13.32% of the primary consolidation. Additionally, the total amount of subsidence resulting from both smectite dehydration and primary consolidation is consistent with the subsidence observed in the field. This study reveals that smectite dehydration appears to be important in assessing and predicting land subsidence in shallow aquifer systems.  相似文献   

12.
 The smectite dehydration theory developed by Ransom and Helgeson was applied for simulation of land subsidence in the Yun-Lin coastal area, Taiwan. The volumetric reduction of smectite clay at equilibrium state was computed by assuming that the dehydration of interlayer water in smectite clay can be described with a regular solid solution reaction. By using the in situ stratigraphic data collected from the subsidence monitoring wells in the simulated area, the amounts of land subsidence caused by smectite dehydration in three scenarios with pressure variation were calculated. The results indicate that significant amounts of land subsidence can be attributed to smectite dehydration. This finding reveals that smectite dehydration is of importance for assessment and prediction of land subsidence. Additionally, the results also indicate the overburden weight has a larger effect on clay dehydration than the effective stress change resulting from over-pumping, although both of them induce relatively minor variations on land subsidence. Received: 23 February 2000 · Accepted: 23 March 2000  相似文献   

13.
上海地下水流三维水动力模型研究   总被引:2,自引:0,他引:2  
本文应用地下水动力数学方程,对上海市区120km~2的范围内,第二含水层以上地层,按地质条件和特征划分了八节点的有限单元进行数值计算,列出了5个典型孔的水位计算与实测对比曲线,拟合结果很好。并在原有的水量开采条件下增加30%的开采量进行了水位预测。为进一步研究上海地下水位变化及地面沉降关系提供了一个新的计算评价手段。  相似文献   

14.
苏州城市规划区Ⅱ承压水开采与地面沉降预防控制研究   总被引:2,自引:1,他引:2  
在孔隙承压水开采与地面沉降的关系上存在2种观点。水、土应力平衡理论认为:只要开采承压水,就会引发应力失衡并导致地面沉降;而水、土动态平衡理论则认为:除非开采水压力至水、土应力平衡面以下,否则不会引发地面沉降。苏州城市规划区第Ⅱ承压水开采水位与地面沉降动态观测表明,在-33m处存在一个天然动态水、土应力平衡面。第Ⅱ承压含水层形成后,经上覆堆积物自重压力长期压缩作用,其水压力具较高的压强.这种天然状态下产生的弹性释放储存量可开采利用多少,取决于开采状态下水、土应力平衡时可消耗压力水柱高度中的水头值。因而地面沉降的根本原因是开采水位超过了-33m,突破了天然状态水、土应力平衡面水位。Ⅱ承压含水层在天然状态受上覆堆积物重力产生的高压强弹性释放储存量现象,可以帮助我们确立该地区孔隙Ⅱ承压水开采不产生地面沉降的临界水位(水、土应力平衡面)。这一点对承压水开采条件、可开采资源性质具有重大实际意义。同样可以应用于饱受地面沉降困扰的无锡、常州及周边地区,为地下水开发利用政策由单一的封井停采转为目标水位控制开采提供了科学依据。同时也为此政策在承压水动力学机制上找到了内在原因。  相似文献   

15.
Land Subsidence of Jakarta (Indonesia) and its Geodetic Monitoring System   总被引:6,自引:2,他引:6  
Abidin  Hasanuddin Z.  Djaja  Rochman  Darmawan  Dudy  Hadi  Samsul  Akbar  Arifin  Rajiyowiryono  H.  Sudibyo  Y.  Meilano  I.  Kasuma  M. A.  Kahar  J.  Subarya  Cecep 《Natural Hazards》2001,23(2-3):365-387
Jakarta is the capital city of Indonesia with a population of about 10 million people, inhabiting an area of about 25 × 25 km. It has been reported for sometime that locations in Jakarta are subsiding at different rates. Up to the present, there has been no comprehensive information about the characteristics and pattern of land subsidence in the Jakarta area. Usually land subsidence in Jakarta is measured using extensometers and ground water level observations, or estimated using geological and hydrological parameters. To give a better picture about land subsidence, geodetic-based monitoring systems utilizing leveling and GPS surveys have also been implemented.The land subsidence characteristics of Jakarta and its surrounding area areinvestigated using data from three repeated leveling surveys performed in1982, 1991, and 1997, and two repeated GPS surveys conducted in 1997and 1999. Leveling surveys detected subsidence up to about 80 cm duringthe period of 1982–1991, and up to about 160 cm during the 1991–1997period; while GPS surveys observed subsidence up to about 20 cm duringthe period of 1997–1999. Comparison with the hydrological data shows thatland subsidence in Jakarta is strongly related to excessive groundwater extraction.  相似文献   

16.
《全国地面沉降防治规划(2011-2020年)》明确提出了北京市的控沉目标。本文介绍了控沉指标的计算方法,对如何界定区域地面沉降速率的计算范围进行了探讨,提出了基于控沉目标的地面沉降分区标准,最后提出了用好南水北调来水等地面沉降的防控措施,以为北京市切实有效进行地面沉降防治工作提供参考。  相似文献   

17.
Jakarta is the capital city of Indonesia with a population of about 9.6 million people, inhabiting an area of about 660 square-km. In the last three decades, urban development of Jakarta has grown very rapidly in the sectors of industry, trade, transportation, real estate, and many others. This exponentially increased urban development introduces several environmental problems. Land subsidence is one of them. The resulted land subsidence will also then affect the urban development plan and process. It has been reported for many years that several places in Jakarta are subsiding at different rates. The leveling surveys, GPS survey methods, and InSAR measurements have been used to study land subsidence in Jakarta, over the period of 1982–2010. In general, it was found that the land subsidence exhibits spatial and temporal variations, with the rates of about 1–15 cm/year. A few locations can have the subsidence rates up to about 20–28 cm/year. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil, and tectonic subsidence. It was found that the spatial and temporal variations of land subsidence depend on the corresponding variations of groundwater extraction, coupled with the characteristics of sedimentary layers and building loads above it. In general, there is strong relation between land subsidence and urban development activities in Jakarta.  相似文献   

18.
Mining in areas with a high phreatic water surface leads to groundwater exposure and the accumulation of the water in the subsidence basin. The calculation of the volume of water is of high importance. This paper analyzes the seasonal or perennial ponding caused by mining in areas with high phreatic water surfaces. With the help of digital elevation model, the estimated groundwater elevation, and the basis of a mining subsidence prediction model, a model of ponding in subsidence areas has been established. Using this model, the amount of mining subsidence ponding in northern Jining has been calculated. Furthermore, the evolution of ponding has been forecasted. Our experimental results indicate that the average depth of the ponding area is projected to be about 3 m after mine closure. The volume of the new perennial ponding is 0.2–2 million m3 per year and it is negligible to the river confluence in Jining. This model helps in the calculation of the amount of water in the subsidence area and the evaluation of the impact of mining subsidence area on the catchment, which would provide a certain basis for the reclamation and protection of water resources in the locality.  相似文献   

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