机制砂和水玻璃改良弱膨胀土抗压和抗剪强度试验研究

广西地区膨胀土分布广泛，在工程中危害较大，常常需要对其进行改良处治。选用机制砂和水玻璃为改良剂，在两者单独掺入和复合掺入的情况下对广西南宁地区膨胀土进行改良，并通过无侧限抗压试验和直剪试验对该膨胀土强度及刚度进行测定，结果表明：机制砂和水玻璃均能提高该膨胀土的强度和刚度，且强度及刚度均随着掺量的增加而先增大后减小，复合掺入的情况下机制砂会降低水玻璃的改良效果。水玻璃最佳掺量为1%,机制砂最佳掺量为10%。进一步用不同粒径的机制砂对膨胀土进行改良发现，为提高该膨胀土的强度，掺入机制砂的粒径不宜大于0.5 mm。研究结果验证了利用水玻璃改良膨胀土和机制砂代替天然风化砂改良膨胀土的有效性。

Experimental analysis of effect of manufactured sand and water glass on unconfined compressive strength and shear strength of weak expansive soil

In Guangxi province, the expansive soil is widely distributed, and the damage to the project is relatively great. It is essential to improve it. Using manufactured sand and water glass as modifiers, in this study, the expansive soil in Nanning, Guangxi was improved under the condition of mixing them separately or in combination. The strength and stiffness of the expansive soil were measured by unconfined compression test and direct shear test. It was found that both manufactured sand and water glass can improve the strength and rigidity of the expansive soil, and both the strength and rigidity first increase and then decrease with increments of the manufactured sand and water glass amount. The manufactured sand will reduce the improvement effect of water glass in the case of compound mixing. The optimum addition amount of water glass is 1%, the optimum addition amount of manufactured sand is 10%. The expansive soil was further improved with manufactured sand of different particle sizes, and it was found that in order to improve the strength of the expansive soil, the particle size of the manufactured sand should not be greater than 0.5 mm. This study verifies the effectiveness of water glass modified expansive soil and manufactured sand instead of natural weathered sand to improve expansive soil, which can provide a reference for future improvement of expansive soil.