声波透射法在旋喷桩复合地基加固效果评价中的应用

结合襄渝线某段地基加固效果检测实例,介绍声波透射法在旋喷桩复合地基加固效果评价中的应用。提出天然地基加固后旋喷桩体和复合地基波速的最低限值:对旋喷桩体,波速最低限值为1600m·s-1;对复合地基,波速最低限值为1100m·s-1。若加固后旋喷桩体和复合地基的波速均达到上述最低限值,则旋喷桩体的无侧限抗压强度一般可达2MPa～8MPa,复合地基承载力可达250kPa～400kPa。实践表明,声波透射法操作简便、快捷,对现场测试条件要求不高,便于重复测试,而且对测试对象无破坏作用。利用声波透射法的测试结果可以定性评价旋喷桩体和复合地基的均匀性以及相对强度特征。     

铁路岩溶塌陷灾害发育规律及危险性分区研究

本文主要研究了铁路岩溶塌陷灾害发育的物质基础和基本规律,给出了根据线路地表地质地貌以及其它情况判定岩溶塌陷危险性的单因子迭加判定方法,该方法在南昆铁路判定结果和现场钻控结果基本相符具有一定实用价值。     

利用环境同位素预测秦岭特长隧道的突水风险

对比地表水和下部地下水中环境同位素氘(D)和氚(^3H或T)的数据表明，秦岭特长隧道北坡L区域断层的水力传导性差，流经该断层的石砭峪河水与下部地下水无直接的水力联系．利用环境氚定量计算出河水对该段隧道潜在突水水量的贡献不足6％，从而完全排除了石砭峪河水通过F4区域断层溃入该隧道的可能性．     

Prevention of Seepage of Unsaturated Clay by Chemical Treatment

Introduction　　Asanimperviousbarrier ,clayiswidelyusedinmanyfieldssuchaswasteisolation .Theimperviousnessofclayisstableinzoneofsaturation ,butnotstableinzoneofaerationasaresultofalternatewettinganddrying ,whichinducesstructuralporeanddryingfractureandrai…     

Screening of Bioflocculant-Producing Strains and Characteristics of Microbial Flocculation

A high effective bioflocculant-producing strain named LB1 was isolated and screened from the leachate by routine micro-method. The strain was identified as genus Pseudomonas according to the morphologic and physiological-biochemical characteristics of the strain. The biological characteristics of the microbial flocculants produced by LB1 were investigated. The results show that the optimal production period of microbial flocculant using LB1 is 96 h; and the products, found in the fermentation liquor, comprise the extracellular organic matter (EOM) of LB1 generated during LB1 growth and the secondary metabolites in the anaphase of LB1. Meanwhile, the mycelia can improve the performance of the microbial flocculants. Because heat has a greater influence on the active substance in the microbial flocculants than other factors, the activity of the flocculants decreases with increasing temperature and the time of heating. The flocculants can flocculate mud-containing and melanin-containing wastewater effectively with a flocculation ratio of 85.1% and 92. 2% , respectively. The optimal heating temperature varies from 20 to 45 ℃. When flocculating the two wastewater, the flocculating activity of the flocculants is above 57. 7% and 70.9% , respectively, in a wide pH range from 3 to 11.     

成渝线典型路基边坡对降雨过程的响应模拟

成渝铁路典型路基边坡由砂泥岩互层及其风化带组成,顶部为２～５ｍ的砂粘土层。模拟实验表明,边坡对降雨过程的水这及力学响应取决于土层的初始渗透性、降雨方式和降雨量;能够对边坡渗流场和应力场产生明显影响的降雨过程一般应同时满足３个条件：（１）雨前经历过较长时间的炎热天气,土层蒸发强烈、初始渗透性良好;（２）降水过程以中到大雨开始,且持续较长时间;（３）降雨时间长,降水量大。     

路基边坡岩体腐蚀的评价研究

岩体腐蚀是路边基坡变形破坏的前提与基础，本文利用质量传输模拟的方法对某路基边坡的岩体腐蚀过程进行了定量评价，结果表明，地下水对边坡的年腐蚀总量近４０ｔ，年腐蚀深度为２．７ｍｍ。     

铁路沿线岩溶塌陷预测模型

岩溶塌陷的发生受多种因素影响,每一因素都在一定程度上反映了对塌陷形成的作用。同时因素间存在一定的相关关系。以基于主成份分析提出的综合向量替代原有因素向量,消除了影响因素的信息重叠,并体现影响因素的致塌权重,在此基础上,通过马氏距离判别建立岩溶塌陷预测模型。应用结果表明,该预测模型是合理的。     

华蓥山隧道排水的生态环境问题及效应

基于两次现场咨询工作经历及收集的资料,探讨了华蓥山隧道排水造成地下水资源流失,煤系质水入侵及水文徨环失衡等生态环境问题及形成机理,以及同此带来的岩溶入泉枯竭,地下水水质恶化,地表水体污染,地表水土流失等一系列负效应,分析结果表明,隧道长期排水将形成较大规模的降位漏斗,由于该漏斗的扩展,导致在疏干带内较强烈的水文地球化学作用,进而威胁隧道衬砌的稳定性。