Expansion reduction of clayey soils through Surcharge application and Lime Treatment
Expansion reduction of clayey soils through Surcharge application and Lime Treatment
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通过附加费和石灰处理减少粘土的膨胀
DOI：
10.1016/j.cscm.2017.06.003
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发表时间：
2017
影响因子：
6.2
通讯作者：
V. Castaño
中科院分区：
文献类型：
--
作者：
T. López;J. Hernández;J. Horta;E. Rojas;S. López;V. Castaño
膨胀的粘性土会引起楼板和墙体的隆起和开裂。膨胀土的特性归因于膨胀粘土矿物的存在。由于土壤水分的变化，这种土壤会膨胀和收缩。在这项研究中，在天然膨胀土(未经处理的土壤)和石灰处理的土壤中测量了抵消土壤膨胀所需的附加量，从19.61千帕(2百万吨/平方米)开始，一直到19.61千帕的增量。此外，在石灰处理的土壤中，为了减小膨胀，还测定了不同附加量下的石灰量。试验结果表明，未处理土的超载与膨胀量的减小不成正比，这可能是由于土的密度增加所致。事实上，只有最初19.61千帕斯卡的附加费显著减少了扩张。结果表明，在超载78.45 kpa的情况下，土体膨胀量显著降低(1.54%)，可视为膨胀压力。另一方面，用6%的石灰(不加外加量)固结试验土(高压缩性粘土)，确定了最低液限和塑性指数，并进行了膨胀试验。对膨胀土施加超载和石灰处理后，39.22kPa和58.84kpa的超载减小了膨胀，增加了其阻力。这是通过在两种处理土壤(石灰含量分别为2%、4%和6%)下的两种附加值下类似的低膨胀值(没有沉降)得出的结论。结果表明，在不加石灰量的情况下，由于石灰量的减少(6%)，土体膨胀量的降低主要是由于超载量的增加。因此，4%的石灰足以满足19.61千帕的附加费，2%的石灰需要最低39.22千帕的附加费。这表明，在膨胀土上的房屋附加费可以减少土壤膨胀，从而降低任何土壤改良方法和特殊基础的成本。
Expansive clayey soils produce heaving and cracking of floor slabs and walls. Expansive soils owe their characteristics to the presence of swelling clay minerals. This soil expands and contracts due to changes in the moisture content of the soil. In this study the surcharge required to counteract soil expansion was measured in natural expansive soils (untreated soils) and lime treated soils starting at 19.61 kPa (2 Ton/m2) and continuing with increments of 19.61 kPa. Additionaly in lime treated soils the amount of lime was determined under different surcharges in order to reduce the expansion. The test results indicated that the surcharges applied to untreated soils were not proportional to the decrease of expansion which is probably due to the increase of soil density. In fact, only the initial surcharge of 19.61 kPa significantly decreased the expansion. According to the results, the soil expansion was considerably reduced (1.54%) with the surcharge of 78.45 kPa, therefore this surcharge can be considered as the Swelling pressure. On the other hand the soil tested (high compressibility clay) was stabilized with 6% of lime (without surcharges) which was determined with the lowest value of liquid limit and plastic index as well as expansion test. After the application of surcharges and lime treatment to expansive soil, the surcharges of 39.22 kPa and 58.84 kPa decreased expansion and increased their resistance. This was concluded by similar low values of expansion (without settlements) under both surcharges of each treated soil tested (2, 4 and 6% of lime). It can be concluded that the surcharge contributed to the decrease of soil expansion due to the decrease of the amount of lime required (6%) without surcharge. So, 4% of lime was enough for the surcharge of 19.61 kPa and 2% of lime required the surcharge minimum of 39.22 kPa. This shows that the surcharge of a house on expansive soil reduces soil expansion and therefore reduces costs of any method of soil improvement and special foundation.